55

1. Introduction. Traceability in the Archaeological Work

When traceability is present in a productive process, it means that, at every step in the process, information about every product is collected and attached to it without ambiguity. We know all the SURGXFWLRQ�SDUDPHWHUV�RI�D�VSHFL¿F�LWHP�RU�JURXS�RI�items and also who is responsible for this information and when and where these data were collected. This knowledge is always available because it is precisely documented.

Archaeological research is divided in several steps. It is also a chain process that, in the context we ZRUN��VWDUWV�DW�WKH�H[FDYDWLRQ�VLWH�ZKHUH�WKH�¿QGLQJV�are unearthed. These elements are moved to the laboratory in order to be cleaned and inventoried. In the next phase, the reconstruction of ceramic SLHFHV� LV� DGGUHVVHG�� 7KHVH� SLHFHV� PXVW� ¿QDOO\� EH�catalogued and sent to a museum. At every step, archaeologists must record information about the Corresponding author: lopeztor@unizar.es

excavated artefacts. These data must accompany the items in order to assure their provenance, control the validity of the archaeological work and conclusions, and facilitate information exchange. Traceability is essential in the work of an archaeologist, usually following a recording manual where the data to EH� WDNHQ�� WKH�ZD\� WKH� LWHPV�DUH� LGHQWL¿HG�DQG� WKH�FROOHFWLRQ� SURWRFRO� DUH� SUHFLVHO\� GH¿QHG� �3DUNV�Canada 2005, 129). The information is initially UHFRUGHG�LQ�D�¿HOG�QRWHERRN��LQ�SDSHU�RU�HOHFWURQLF�format, and later transferred to an inventory or database. In any of these information repositories, the link between data and artefacts must be clear DQG�WUDFHDEOH��6DQGV�������

As will be explained below, in a traceability system any item or group of items must be precisely LGHQWL¿HG� WR� WUDFH� LWV� HYROXWLRQ� WKURXJK� WKH� FKDLQ�SURFHVV��7KH�LGHQWL¿FDWLRQ�FRGH�LQ�DUFKDHRORJ\�FDQ�EH� GLUHFWO\� DWWDFKHG� WR� WKH� HOHPHQW� �DOSKDQXPHULF�FRGHV� KDQGZULWWHQ� RU�4XLFN� 5HVSRQVH� �45�� FRGHV�stuck on it �0DUWtQH]�0RUHQR�� *RQ]iOH]� 0DUFpQ��DQG�0RUD�7RUFDO� ������ ��������) or can be stored

Identifying and Tracing Archaeological Material with RFID Tags

Ana María López, Ana María Salinas, Eduardo Pascual, Guillermo Ignacio Azuara, Gloria Fernández

University of Zaragoza, Spain

Elena Gallego Segeda Celtiberian Studies Centre, Spain

Francisco BurilloUniversity of Zaragoza, Spain

Abstract:,Q�WKLV�SDSHU�ZH�SURSRVH�WR�ODEHO�DUFKDHRORJLFDO�PDWHULDOV�ZLWK�5),'��5DGLR)UHTXHQF\�,'HQWL¿FDWLRQ��tags in order to identify them in an unambiguous way. In this way, it is possible to trace the relevant LQIRUPDWLRQ�DVVRFLDWHG�WR�WKHP��WKURXJK�DOO�WKH�SKDVHV�RI�DUFKDHRORJLFDO�ZRUN��IURP�¿HOGZRUN�WR�PXVHXP�VWRUDJH��7KH�V\VWHP�KDV�EHHQ�VSHFL¿FDOO\�GHVLJQHG�WR�EH�LQWHJUDWHG�ZLWK�WKH�ZRUNLQJ�SURFHGXUHV�RI�WKH�archaeological team working on the Segeda project��6HJHGD������. This technique improves archaeological work in several ways. First, it speeds up the process of collecting, saving, updating and duplicating the data associated with every piece of material. Second, it increases the information that can be stored with the material and can be retrieved without connection to the database. Third, it reduces human error in transcribing information. Finally, RFID labelling facilitates the process of localizing stored material and controlling its movement.

Keywords: Information Management, Traceability, Radiofrequency Information

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ZLWK� LW� �D� SDSHU� FDUG� RU� VKHHW� VDYHG� LQ� WKH� VDPH�container). The information related to each artefact that is going to be measured and recorded can be LQ¿QLWH��DQG�PXVW�EH�VHOHFWHG�LQ�WHUPV�RI�UHOHYDQFH�to the research. The aims of the excavation work will GH¿QH�ZKLFK�GDWD� IURP�D�KXJH�QXPEHU�RI�SRVVLEOH�observations will be collected and associated with WKH� LGHQWL¿FDWLRQ� FRGH�� 7KH� JDWKHUHG� LQIRUPDWLRQ�FDQ�EH�XVHG�ZLWK�D�FODVVL¿FDWLRQ�SXUSRVH�IROORZLQJ�NQRZQ� DQG� ¿[HG� FULWHULD�� %XW� GL̆HUHQW� HOHPHQWV�can also be grouped on the basis of more subjective criteria, established dynamically in the course of the research process. The analysis unit can change from a phase to the next one and new data are incorporated into the description of these units.

Any traceability system must be integrated to the work procedure of the archaeological research group. In our case, this system is going to be LPSOHPHQWHG� DW� WKH� H[FDYDWLRQ� VLWH� DW� 6HJHGD� LQ�6SDLQ��

This paper continues with an overview of the concept of traceability and a basic description of WKH� UDGLRIUHTXHQF\� LGHQWL¿FDWLRQ� WHFKQRORJ\� DQG�its main advantages. Next, the context where the system is going to work is introduced. In section 5, the design of the traceability system is detailed. Finally, the main conclusions and future steps are set out.

2. Elements of a Traceability System

The basic elements of a traceability system are WKH�LGHQWL¿FDWLRQ�WHFKQRORJ\��WKH�WUDFHDELOLW\�VWHSV��the management information system and the quality evaluation procedure.

7R�GHYHORS�D�WUDFHDELOLW\�V\VWHP��ZH�PXVW�¿UVW�choose the technology used to identify the objects. In order to trace the evolution of an object through D� FKDLQ� SURFHVV�� LW� PXVW� EH� SUHFLVHO\� LGHQWL¿HG��7KH�LGHQWL¿FDWLRQ�FRGH�FDQ�EH�PDQXDOO\�ZULWWHQ�RQ�D�SDSHU� WDJ�RU�RQ� WKH� HOHPHQW� LWVHOI� �WKHVH� DUH� WKH�LGHQWL¿FDWLRQ�PHWKRGV�XVHG� VR� IDU� DW� 6HJHGD� VLWH���$�GL̆HUHQW�DSSURDFK�LV�WKH�XVH�RI�RQH�GLPHQVLRQDO�RU�WZR�GLPHQVLRQDO�FRGH�EDUV�WKDW�DUH�DXWRPDWLFDOO\�read by means of a scanner �0DUWtQH]�0RUHQR��*RQ]iOH]�0DUFpQ��DQG�0RUD�7RUFDO���������������. ,Q�RXU�V\VWHP��UDGLRIUHTXHQF\�LGHQWL¿FDWLRQ��5),'��tags are used. These elements will be described later

LQ�WKLV�SDSHU��$OVR�WKH�OHYHO�RI�LGHQWL¿FDWLRQ�PXVW�EH�GH¿QHG��$�FRGH�FDQ�VWDQG�IRU�D�VLQJOH�HOHPHQW��RU�D�JURXS�RI�HOHPHQWV�FDQ�VKDUH�WKH�VDPH�LGHQWL¿FDWLRQ�QXPEHU�� 7KLV� LGHQWL¿FDWLRQ� OHYHO� FRUUHVSRQGV� WR�the analysis unit established at every stage in the research.

2QFH�WKH�LWHPV�DUH�LGHQWL¿HG��ZH�FDQ�FRQWURO�their progress in the traceability chain. The WUDFHDELOLW\� FKDLQ�GH¿QHV� WKH� FRQWURO� SRLQWV� RI� WKH�system:

• At which places the data are going to be collected.

• When the data collection takes place.

• Which data are going to be collected

• How the data are taken and transmitted to the LQIRUPDWLRQ�UHSRVLWRULHV��ZKDW�LV�GLUHFWO\�UHODWHG�WR�WKH�LGHQWL¿FDWLRQ�WHFKQROogy)

• Who is responsible for the collected information.

The information storage repositories must be established and the way the information is saved GH¿QHG�� 7KH� GDWD� FDQ� EH� VWRUHG� LQ� RQH� RU� VHYHUDO�sites and formats. This redundancy guarantees the information recovery if one of the repositories fails and also makes it possible to read the data in GL̆HUHQW�ZD\V��E\�YLVXDO�LQVSHFWLRQ��XVLQJ�D�VFDQQHU�or accessing to a digital database.

The collected data can be used to take decisions about the process, but generally, the purpose is to document and trace the activity done. Communication channels must be carefully GH¿QHG�� ,W� LV�HVSHFLDOO\� LPSRUWDQW�ZKHQ�WKH� WUDFHG�DUWHIDFWV� DUH� WUDQVIHUUHG� WR� GL̆HUHQW� ORFDWLRQV� RU�HYHQ� VWXGLHG� E\� GL̆HUHQW� LQVWLWXWLRQV�� 7UDFHDELOLW\�FDQ� KDYH� GL̆HUHQW� VFRSHV�� %DFNZDUGV� WUDFHDELOLW\�GHVFULEHV� WKH�SDVW�KLVWRU\�RI� HYHU\� LGHQWL¿HG� LWHP��,QWHUQDO� WUDFHDELOLW\� GH¿QHV�ZKDW� SURFHVVHV� IROORZ�the elements at one location. Forward traceability GHDOV� ZLWK� WKH� GH¿QLWLRQ� RI� WKH� IXWXUH� VLWXDWLRQ�of the elements: where the items are going to be moved, how they are going to be carried and when the transfer is planned. The documentation must be clear and precise and, in some cases, it is important WR�HVWDEOLVK�D�UROH�EDVHG�DFFHVV�FRQWURO�IRU�GL̆HUHQW�users.

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57

Finally, the quality of the traceability system must be systematically measured in order to undertake improvement and correction actions. A JURXS�RI�PHDVXUDEOH�LQGLFDWRUV�PXVW�EH�GH¿QHG�WR�determine whether the traceability system meets the required performance criteria.

3. 5DGLRIUHTXHQF\�,GHQWL¿FDWLRQ��5),'�

5DGLRIUHTXHQF\�LGHQWL¿FDWLRQ��5),'��EHORQJV�WR� WKH� JURXS� RI� DXWRPDWLF� LGHQWL¿FDWLRQ� DQG� GDWD�FDSWXUH��$,'&��WHFKQRORJLHV�� OLNH�FRGH�EDUV��VPDUW�FDUGV� RU� WHFKQLTXHV� RI� ELRPHWULF� LGHQWL¿FDWLRQ��,W� LV� EDVHG� RQ� WKH� XVH� RI� D� XQLTXH� LGHQWL¿FDWLRQ�code for every element. This code is known as 8QLTXH� ,GHQWLI\LQJ� 'LJLW� �8,'�� DQG� LW� LV� VWRUHG�LQ� WKH� LQWHUQDO� PHPRU\� RI� D� 5),'� WDJ�� ,Q� RUGHU�WR� DXWRPDWLFDOO\� LGHQWLI\� RQH� LWHP�� D� 5),'� WDJ� LV�DWWDFKHG�WR�LW��7KH�8,'�WKDW�VWDQGV�IRU�WKLV�WDJ�DQG�for the object can be read and communicated to a FRQWURO� V\VWHP� E\� PHDQV� RI� DQ� 5),'� UHDGHU� WKDW�interrogates the tag using an electromagnetic wave of the radio wave frequency band. The tag answers with its own radiofrequency signal. In this way, we NQRZ� WKDW� RQH� VSHFL¿F� LWHP� KDV� SDVVHG� WKURXJK�WKH�UHDG�UDQJH�RI�WKH�5),'�UHDGHU�LQ�D�NQRZQ�WLPH�interval. The process is outlined in Figure 1. No SUHFLVH�DOLJQPHQW�EHWZHHQ�WKH�UHDGHU�DQG�WKH�5),'�WDJ� LV� UHTXLUHG�� ,I� WKH� UHDGHU� LV� FRQ¿JXUHG� WR� VFDQ�for tags continuously, it is possible to control which elements have passed near the reader’s position without any human interaction.

7KH�EDVLF�HOHPHQWV�RI�DQ�5),'�V\VWHP�DUH�WKH�5),'�WDJ�� WKH�5),'�UHDGHU�DQG�WKH�5),'�VRIWZDUH�NQRZQ� DV� PLGGOHZDUH� �*ORYHU� DQG� %KDWW� �������7KH�5),'� WDJ�DFWV�DV� WKH� LGHQWL¿FDWLRQ�HOHPHQW�DV�mentioned above. It is formed by an electronic chip, an antenna and a storage memory. This memory has DOZD\V�UHVHUYHG�EORFNV�ZKHUH�WKH�XQLTXH�FRGH�8,'�LV�VDYHG��7KHVH�VSHFL¿F�EORFNV�FDQQRW�EH�PRGL¿HG�VR�WKH�LQWHJULW\�RI�WKH�LGHQWL¿FDWLRQ�FRGH�LV�JXDUDQWHHG��This basic memory can be extended to save more information. There is reserved space for storing access passwords, error detection and correction FRGHV� �DV� WKH� &\FOLF� 5HGXQGDQF\� &RGH� &5&�� RU�3URWRFRO�&RQWURO�ELWV��7KH�DGGUHVV�RI� WKHVH�GDWD� LQ�WKH�PHPRU\�PDS�LV�V\VWHP�GH¿QHG��)LQDOO\��WKH�WDJ�PHPRU\� FDQ� KDYH� D� EDQN�� WKH� XVHU�PHPRU\� ]RQH��ZKHUH�QHZ�GDWD�FDQ�EH�ZULWWHQ��UHDG�DQG�PRGL¿HG�ZLWK�WKH�5),'�UHDGHU��7KH�IRUPDW�DQG�VL]H�RI�WKH�GDWD�

DUH�XVHU�GH¿QHG��,Q�WKLV�ZD\��SDUW�RI�WKH�WUDFHDELOLW\�parameters can be dynamically saved inside the LGHQWL¿FDWLRQ� HOHPHQW� DQG� WUDYHO� ZLWK� WKH� REMHFW�LGHQWL¿HG��7KH�WDJV�FDQ�DSSHDU�LQ�PXOWLSOH�SK\VLFDO�IRUPDWV�WKDW�FDQ�DGDSW�WR�GL̆HUHQW�DSSOLFDWLRQV�DQG�work environments.

7KH�5),'� UHDGHUV� KDYH� VHYHUDO� IXQFWLRQV�� ,Q�most cases, they provide to the tags with the energy they need to transmit their radiofrequency signals �WKRXJK� WKHUH� DUH� DFWLYH� WDJV� WKDW� KDYH� D� EDWWHU\���7KH\�FRPPXQLFDWH� WR� WKH� WDJV� WKURXJK�UDGLR�ZDYH�signals and get, for example, the Unique Code that LGHQWL¿HV� WKH� LWHP�� 7KLV� LQIRUPDWLRQ� LV� VHQW� IURP�the reader to the information system. The control system can be the origin of additional information that is saved in the user memory of the tag. The UHDGHU�ZULWHV��UHDGV��DQG�PRGL¿HV�WKHVH�GDWD�LI�WKH�tag has a user memory bank.

7KH�UHDGHUV�FDQ�EH� LPSOHPHQWHG� LQ�GL̆HUHQW�formats. There are handheld readers and readers WKDW� DUH� DWWDFKHG� WR� FRPSXWHUV�� 6RPH� UHDGHUV� DUH�simple and inexpensive, while others are more complex and robust devices that can work in very harsh environments. In some cases the tags are ZULWWHQ�LQVLGH�WKH�UHDGHU��OLNH�LQ�5),'�SULQWHUV��EXW�JHQHUDOO\� WKH� WDJV� MXVW�QHHG� WR�EH� LQVLGH� WKH�5),'�UHDGHU�UHDG�UDQJH��7KH�VL]H�RI� WKLV�FRPPXQLFDWLRQ�DUHD� GHSHQGV� RQ� WKH� IUHTXHQF\� RI� WKH� UDGLR�ZDYH�VLJQDOV� XVHG� DQG� RQ� WKH� VL]H� RI� WKH� DQWHQQDV� RI�readers and tags.

7KH� WKLUG�HOHPHQW�RI� WKH�5),'�V\VWHP� LV� WKH�5),'� PLGGOHZDUH� RU� VRIWZDUH� WKDW� FRQYHUWV� ORZ�

Figure 1. An RFID tag and a reader communicate by means of electromagnetic waves.

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58

OHYHO� 5),'� KDUGZDUH� LQIRUPDWLRQ� IURP� WKH� UHDGHU�into information useful to the system. The data can be used in an event driven process or merely can be saved in a system database. Though there are commercial middleware, the versatility of 5),'�V\VWHPV� LV�EDVHG�RQ�WKH�SRVVLELOLW\�RI�GHVLJQ�DSSOLFDWLRQ�VSHFL¿F�SURJUDPPHV�

There are several parameters that determine WKH�EHKDYLRXU�RI�DQ�5),'�V\VWHP��:H�KLJKOLJKW�KHUH�the importance of the frequency of the waves use to communication. There are several frequencies DYDLODEOH� IRU�5),'� V\VWHPV�� /RZ� IUHTXHQF\� �������.+]���+LJK�)UHTXHQF\��������0+]��DQG�8OWUD�+LJK�)UHTXHQF\� EDQGV� ����� 0+]� DQG� �������� 0+]���6RPH�5),'�DSSOLFDWLRQV��OLNH�DQLPDO�LGHQWL¿FDWLRQ��FDQ�RQO\�XVH�RQH�EDQG��/)���7KH�PDLQ�SHUIRUPDQFH�GL̆HUHQFH�LV�WKH�LQFUHPHQW�RI�WKH�UHDGHU�UDQJH�ZLWK�frequency. If the elements to be tagged are metallic or have a high water content, only HF system can be used to prevent detection failures.

• 5),'�WHFKQRORJ\�R̆HUV�VHYHUDO�DGYDQWDJHV�RYHU�RWKHUV�DXWRPDWLF�LGHQWL¿FDWLRQ�WHFKQRORJLHV�OLNH�code bars or biometric techniques when used in a traceability system:

• 7KH� UHDG� RI� WKH� LGHQWL¿FDWLRQ� FRGH� LV� DOPRVW�

instantaneous and can take place even without human interaction. It is not necessary to align SUHFLVHO\� D� VFDQQHU�ZLWK� WKH� LGHQWL¿FDWLRQ� LWHP��DV� LQ�WKH�FDVH�RI�EDU�FRGHV�RU�GLJLWDO�SULQWV�� WR�JHW�WKH�LQIRUPDWLRQ��%HLQJ�FORVH�WR�D�5),'�UHDGHU�is enough.

• 5),'�WDJV�FRQWDLQV�D�XQLTXH�FRGH��GL̆HUHQW�IURP�the case of code bars) There are no identical 5),'�WDJV�

• 5),'� WDJV� FDQ� G\QDPLFDOO\� VWRUH� H[WUD�information from the traceability process. These GDWD�FDQ�EH�PRGL¿HG�DW�DQ\�WLPH�

• 5),'�V\VWHPV�DUH�ÀH[LEOH�DQG�YHUVDWLOH�GXH�WR�WKH�SRVVLELOLW\� RI� IUHTXHQF\� VHOHFWLRQ�� WKH� GL̆HUHQW�physical support for the tags or the middleware design.

4. Segeda Site

7KH� YHUVDWLOLW\� RI� 5),'� WHFKQRORJ\� PDNHV�possible to adapt the traceability system to the current working methodology of the group UHVHDUFKLQJ�WKH�DUFKDHRORJLFDO�VLWH�RI�6HJHGD����

³6HJHGD�,´�LV�ORFDWHG�LQ�WKH�1RUWKHDVW�RI�6SDLQ�FORVH� WR� WKH� YLOODJH� RI� 0DUD� LQ� =DUDJR]D� SURYLQFH��)LJ������7KLV�VLWH�LV�VLWXDWHG�FORVH�WR�WKH�EDVLQ�RI�WKH�(EUR�5LYHU��QHDU�LWV�FRQÀXHQFH�ZLWK�WKH�-DOyQ�5LYHU��6HJHGD�ZDV�D�FHOWLEHULDQ�FLW\�VWDWH�� WKH� ODUJHVW�RQH�LQ� QRUWKHUQ� RI� 6SDLQ�� H[WHQGLQJ� RYHU� ��� KHFWDUHV��It played an important role in the Roman Wars in ZKLFK�WKH�,EHULDQ�3HQLQVXOD�ZDV�FRQTXHUHG��'XULQJ�WKH�&HOWLEHULDQ�:DUV������DQG�����%&��6HJHGD�ZDV�devastated by roman soldiers. It is possible to put WKH�GDWH�����%&�OLNH�³WHUPLQXV�DQWH�TXHP´�IRU�DOO�WKH�PDWHULDOV�IRXQG�LQ�WKLV�VLWH��%XULOOR����������������

$UFKDHRORJLFDO�ZRUN�EHJDQ�DW�6HJHGD�LQ�������%HWZHHQ������DQG������VXUIDFH�SURVSHFWLRQV�ZHUH�undertaken to delimit the site. From 2000 year until QRZ� ������� DUFKDHRORJLFDO� H[FDYDWLRQV� KDYH� EHHQ�FDUULHG�RXW�LQ�GL̆HUHQW�DUHDV�RI�WKH�VLWH��)LJ�����

5. Design of the RFID based traceability system

As outlined above, the design of a traceability V\VWHP� LPSOLHV� WKH� VHOHFWLRQ� RI� DQ� LGHQWL¿FDWLRQ�

Figure 2. Segeda site is localized in the North-East of Spain.

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59

WHFKQRORJ\�� WKH�GH¿QLWLRQ�RI� WKH� WUDFHDELOLW\�FKDLQ��the information repositories and communication FKDQQHOV�DQG��¿QDOO\�WKH�ZD\�WKH�V\VWHP�LV�HYDOXDWHG��Our work is based on a number of premises:

• Full integration with the traceability methods XVHG�VR�IDU�E\�WKH�6HJHGD�UHVHDUFK�JURXS�

• Increase the automation of data collection and recovery

• Reduce uncertainty regarding provenance.

�����,GHQWL¿FDWLRQ�WHFKQRORJ\

:H� XVH� 5),'� WDJV� RSHUDWLQJ� LQ� WKH� 8+)�EDQG�WR�LGHQWLI\�WKH�¿QGLQJV�RI�WKH�VLWH��7KHVH�WDJV�KDYH� D� XVHU�PHPRU\� RI� ���� ELWV�� D� VL]H� RI� ��� [� ���mm and are attached to an adhesive inlay. Their SULFH� LV� ��� HXUR� FHQWV� HDFK�� IRU� DQ� RUGHU� RI� �����XQLWV�� *UHDWHU� TXDQWLWLHV� RUGHUV� DOORZ� IRU� ORZHU�XQLW� SULFHV�� 7KH� LGHQWL¿FDWLRQ� OHYHO� UHVHPEOHV� WKH�WUDFHDELOLW\�SURWRFRO�XVHG�VR�IDU�DW�6HJHGD��,QLWLDOO\��JURXS� LGHQWL¿FDWLRQ� LV� DGGUHVVHG�� )UDJPHQWV� WKDW�DUH� IRXQG� WRJHWKHU� VKDUHG� D�5),'� WDJ��2QO\�ZKHQ�a whole piece is found or after reconstruction of a FHUDPLF�HOHPHQW��VLQJOH�LGHQWL¿FDWLRQ�OHYHO�LV�XVHG�

5.2. Traceability chain

The traceability chain consists of four steps �)LJ�� ���� 7KH� ¿UVW� SODFH� ZKHUH� LQIRUPDWLRQ� LV�collected is at the excavation site, at the moment an artefact is found. The artefacts are moved to the archaeological laboratory where they are cleaned and inventoried and, afterwards, follow a reconstruction

process if possible. Finally, some of these pieces are transferred to a museum. These four control points will be described in more detail below. The data that are going to be traced and saved are the same RQHV�WKDW�KDYH�EHHQ�UHFRUGHG�VR� IDU�E\�WKH�6HJHGD�research group.

5.3. Information repositories

7KH� LQIRUPDWLRQ� LV� VDYHG� LQ� IRXU� GL̆HUHQW�IRUPDWV��DQ�HOHFWURQLF�GDWDEDVH��WKH�5),'�WDJ�XVHU�memory, on the archaeological item itself with an LQN�PDUN�� DQG� KDQGZULWWHQ� RQ� WKH�5),'� WDJ�� 7KLV�redundancy is intended to keep the old storage formats and the new ones working together in the test period. Not all the data are saved in the four formats.

The traceability system is intended to an internal use. All members of the research group have unlimited access to the information saved LQ� WKH� GDWDEDVH� DQG� WKH� 5),'� WDJV�� ,I� QHFHVVDU\��both repositories can be protected with an access SDVVZRUG�� $� 5),'� WDJ� FDQ� EH� ORFNHG� VR� WKDW� RQO\�DXWKRUL]HG�XVHUV�FDQ�UHDG�WKH�VWRUHG�LQIRUPDWLRQ�

5.4. Evaluation of the traceability system

In order to evaluate the performance of the traceability system, several items must be measured. $V�LQLWLDOO\�WKH�5),'�V\VWHP�LV�JRLQJ�WR�ZRUN�WRJHWKHU�ZLWK�WKH�ROG�LGHQWL¿FDWLRQ�DQG�FRQWURO�PHWKRGV��LW�LV�possible to compare aspects like:

Figure 3. Excavation areas at Segeda site.

Figure 4. Check points of the traceability system.

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• Wrong data.

• /RVW�GDWD�

• Time requirements.

Additionally, information from the users �DUFKDHRORJLFDO� UHVHDUFKHUV� DQG� FROODERUDWRUV��must be analysed. Opinions about the ease of use, the robustness of the devices or the clarity of the software must be taken into account to implement improvements to the system.

5.5 The traceability checkpoints

This section details the characteristics of each checkpoint of the traceability chain. First, the actions that must be carried out at each location are described. Then, we explain how these activities DUH�PRGL¿HG�EHFDXVH�RI�WKH�LQWHJUDWLRQ�RI�WKH�5),'�technology. Finally, the required hardware is listed.

6WHS����([FDYDWLRQ�VLWH�

7KH� ¿UVW� SRLQW� IRU� GDWD� FROOHFWLQJ� LV� WKH�excavation site. When similar items are found in the VDPH�VWUDWLJUDSKLF� OHYHO�DQG�]RQH�� WKH\�DUH�EDJJHG�together. A paper card is used to write information about the date of recollection, the physical location and the material of the artefacts. This card is saved inside the bag. The data included in this card are shown on Table 1. These bags are sent to the archaeological laboratory.

In the new system, the paper card attached WR� HDFK� EDJ� LV� UHSODFHG� E\� D� 5),'� WDJ� DQG� WKH�information saved in the memory of this tag. As this tag has a paper inlay, the handwritten information can be kept.

6RPH�RI�WKH�GDWD�WR�EH�VDYHG�DW�WKH�H[FDYDWLRQ�site are common to all the elements found on the VDPH�GD\��6RPH�JHRJUDSKLF�DQG�WHPSRUDO�GDWD�DUH�known in advance, so we have decided to record WKHP� LQ� D�QXPEHU�RI�5),'� WDJV�EHIRUH� DUULYLQJ� WR�WKH�¿HOG��,I�WKHVH�WDJV�DUH�QRW�XVHG��WKH�GDWD�FDQ�EH�PRGL¿HG�EHFDXVH� WKH� WDJ�PHPRU\� LV� UHZULWDEOH�� ,Q�this way, recording work at the site is reduced. The data are provided by the user through the touch LQWHUIDFH�RI�D�KDQGKHOG�5),'�UHDGHU��)LJ������7KHQ�the tag is recorded just by clicking a button. The LQIRUPDWLRQ� VDYHG� FDQ� EH� FKHFNHG� RU� PRGL¿HG� DW�any time.

The information is also stored in a local database inside the device. At the end of the day, it is transferred to the global traceability database. This database has the same structure as the one used so IDU�E\�6HJHGD¶V�UHVHDUFK�JURXS��7KH�RQO\�GL̆HUHQFH�LV�WKDW�D�QHZ�¿HOG��FRQWDLQLQJ�WKH�WDJ�8,'��PXVW�EH�added to the tables of the database.

The hardware required at this location is an 5),'�UHDGHU��D�FRPSXWHU�DQG�D�SULQWHU��LI�WKH�FDUG�

Figure 5. Handheld RFID reader.

EXCAVATION SITE

Geographic information ����=RQH������/RW��

• Area ��6HFWRU��6SDFH

��6WUDWLJUDSKLF�XQLW��6TXDUH

• Total station coordinates• Height

Chronological information • Campaign ����'DWH��

Element information ��0DWHULDO��%DJ�QXPEHU

Table 1. Data to be collected at the excavation site. Common data are shaded.

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61

used so far is going to be created) before excavation DQG� D� KDQGKHOG� 5),'� UHDGHU� GXULQJ� H[FDYDWLRQ��7KH�5),'�UHDGHU�FDQ�EH�WKH�VDPH��DV�WKH�KDQGKHOG�reader can communicate to a computer.

6WHS����$UFKDHRORJLFDO�ODERUDWRU\�

Once in the laboratory, the fragments are cleaned and marked with a number that is shared by all the elements of the same bag. This internal LGHQWL¿FDWLRQ�FRGH��NQRZQ�DV�³VLJOD´��LV�WKH�RQH�XVHG�in inventory and contains information about the \HDU�DQG�DUHD�RI�ZRUN��WZR�GLJLWV���D�FRGH�DVVLJQHG�E\� WKH�PXVHXP� WR� WKH� H[FDYDWLRQ� �WZR�GLJLWV��� WKH�LQYHQWRU\�QXPEHU��D�FRUUHODWLYH�QXPEHU�IRUPHG�E\�IRXU�GLJLWV� WKDW�GL̆HUHQWLDWHV�WKH�EDJV�ZLWK�VLPLODU�data) and a character that indicates the material of the fragments inside the bag. Its structure is shown LQ�)LJXUH���

%HVLGHV�� WKH� FRQWHQW� RI� WKH� EDJ� LV� DQDO\VHG��The fragments that seem to be part of the same piece are packaged in a second bag. A new card is created for this new bag with the same information that contains the card of the original bag. This new EDJ�LV�VDYHG�LQVLGH�WKH�LQLWLDO�EDJ��)LJ�����

In our system, the inventory number should be the new information that must be added to the 5),'� WDJ��+RZHYHU�� VRPH�RI� WKH�GDWD� WKDW� IRUPHG�SDUW� RI� WKH� ³VLJOD´� DUH� DOUHDG\� UHFRUGHG� LQ� WKH� WDJ�memory so, it is not necessary to save the whole FRGH��)XUWKHU��WKH�5),'�VRIWZDUH�FDQ�DXWRPDWLFDOO\�calculate the codes that are going to be written on the fragments.

:KHQ� WKH� HOHPHQWV� RI� WKH� EDJ� DUH� FODVVL¿HG��LW� LV� WKH� PRPHQW� WR� FRQ¿UP� WKHLU� PDWHULDO� DQG�correct it if necessary. The number of sherds is FRXQWHG� DQG� DGGHG� WR� WKH� 5),'� WDJ� DQG� DOVR� WKH�QXPEHU�RI�HOHPHQWV�QRW�LGHQWL¿HG���,I�LW�LV�QHFHVVDU\�WR�GXSOLFDWH�WKH�WDJ��WKH�5),'�UHDGHU�MXVW�UHDGV�WKH�original tag and records its data in a second tag at the same time that saves it in the database. Table 2

gathers the information to be collected at this step of the traceability system.

The hardware elements required to implement the traceability system in the laboratory are the same that those used in the excavation site.

6WHS����5HFRQVWUXFWLRQ�

The third control point is the reconstruction ODERUDWRU\� WKDW� FDQ� EH� WKH� VDPH� RU� GL̆HUHQW� WKDQ�the previous one. The aim is to join fragments in order to obtain a new element. This piece will be LGHQWL¿HG�ZLWK�D�QHZ�QXPEHU�DQG�D�QHZ�FDUG��7KH�SUHYLRXV�FODVVL¿FDWLRQ�LQ�EDJV�PDNHV�WKH�WDVN�HDVLHU��7KH�XQLGHQWL¿HG�DUWHIDFWV�DUH�OHIW�LQ�WKH�RULJLQDO�EDJ�whose information card is destroyed.

7KH�5),'�V\VWHP�PXVW�FUHDWH�D�QHZ�WDJ�WR�EH�attached to the piece, but also it is going to update the tag of the original bags that is not going to be eliminated.

Figure 6. Structure of the internal code or “sigla” used by Segeda group.

Figure 7�� :KHQ� VRPH� IUDJPHQWV� DUH� LGHQWL¿HG� DV�belonging to the same ceramic piece they are bagged together. The new bag is saved inside the original one. Both bags contain cards with the same data.

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7KH�QHZ�5),'�WDJ�VSHFL¿F�IRU�WKH�UHFRQVWUXFWHG�SLHFH�PXVW� VWRUH� WKH� FRGH� WKDW� LGHQWL¿HV� LW�� ,Q� WKH�inventory and database the link between this code DQG� WKH� ³VLJOD´� RI� WKH� RULJLQDO� VKDUGV� LV� FUHDWHG��In the tag memory the numbers that identify the source bags are recorded. This data will help to follow backwards traceability without consulting the inventory or database.

At the same time, the existent tag is updated. The information added indicates that a number of fragments from the bag are part of a piece with a known number. In this way forward traceability is fed back. All the new information is gathered in 7DEOH���

When a new piece is reconstructed, we leave WKH� JURXS� LGHQWL¿FDWLRQ� OHYHO� �RQH� WDJ� IRU� D� JURXS�RI�IUDJPHQWV��DQG�DVVXPH�VLQJOH�LWHP�LGHQWL¿FDWLRQ�level.

The required hardware is the same as the used in the previous phase.

6WHS����0XVHXP�WUDQVIHU�

When an artefact is transferred to a museum, it must be accompanied by a record including all the relevant information in the format set by this institution. Assuming the museum agrees to use WKH�5),'�V\VWHP��LW�PD\�EH�QHFHVVDU\�WR�DGG�PRUH�GDWD�� EXW� QRW� WR� PRGLI\� WKH� ¿HOGV� DOUHDG\� VWRUHG��:H� ZRXOG� KDYH� WR� DGDSW� WKH� 5),'� DSSOLFDWLRQ�

WR� YLVXDOL]H� WKH� LQIRUPDWLRQ� ¿HOGV� IROORZLQJ� WKH�PXVHXP�UHTXLUHPHQWV��7KH�5),'�WDJV�EHORQJLQJ�WR�the traceability system should be updated with the date of the departure of the piece. At this moment, there is no contact with any host museum.

5.6. Software interface

The software application developed to read DQG�ZULWH�LQIRUPDWLRQ�IURP�WKH�5),'�WDJV�KDV�EHHQ�created using the programming language Visual C#. This language eases the creation of visual interfaces WKDW�VLPSOLI\�WKH�XVHU�RSHUDWLRQ��%HVLGHV��WKH�5),'�devices can be controlled with a set of functions written in this language that can also easily communicate with databases. The basic events that can be controlled with the application software are tracing tags, reading and writing tags and deleting WDJV��)LJ�����

7R� LQWHUDFW� ZLWK� DQ� 5),'� WDJ�� ZH�PXVW� ¿UVW�EH�VXUH�WKDW�LW�LV�LQVLGH�WKH�UHDGHU�UDQJH��6R��EHIRUH�writing or reading a tag it is necessary to trace which tags are near the reader.

7KH� 8,'¶V� RI� WKHVH� WDJV� DUH� OLVWHG� RQ� WKH�LQWHUIDFH��)LJ������,Q�WKLV�ZD\�ZH�FDQ�VHOHFW�WKH�WDJ�we are going to work with. Choosing the read menu, DOO�WKH�GDWD�VWRUHG�LQVLGH�WKH�5),'�WDJ�DUH�GLVSOD\HG�in an interface that has been designed in order to UHVHPEOH�WKH�)LOHPDNHU�UHFRUGLQJ�¿OHV�XVHG�VR�IDU��as shown on Figure 10.

ARCHAEOLOGICAL LABORATORY: Cleaning and inventory

2ULJLQDO�EDJ��WDJ�FUHDWHG�DW�WKH�H[FDYDWLRQ�VLWH� • Inventory number that completes sigla code.��1XPEHU�RI�IUDJPHQWV�LGHQWL¿HG�WR�EHORQJ�WR�D�SLHFH

• Number of amorphous

6HFRQGDU\�EDJ��WDJ�GXSOLFDWHG�IURP�WKH�RULJLQDO�RQH�DW�WKH�ODERUDWRU\�

��$OO�WKH�GDWD�IURP�WKH�RULJLQDO�5),'�WDJ• Number of fragments.

Table 2. Data to be collected at the archaeological laboratory. Cleaning and inventorying phase.

ARCHAEOLOGICAL LABORATORY: Reconstruction

([LVWLQJ�WDJV�DUH�XSGDWHG� ��,GHQWL¿FDWLRQ�FRGH�V�RI�WKH�SLHFH�V�FUHDWHG�IURP�IUDJPHQWV�IURP�WKLV�EDJ�

New piece RFID tag ��,GHQWL¿FDWLRQ�FRGH�RI�WKH�SLHFH�• ,GHQWL¿FDWLRQ�FRGH��VLJOD��IURP�WKH�EDJV�WKDW�KDYH�FRQWULEXWHG�WR�WKH�SLHFH�

Table 3. Data to be collected at the archaeological laboratory. Reconstruction phase.

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63

All the important data are included and can be FRPSOHWHG�RU�PRGL¿HG�IURP�D�WRXFK�VFUHHQ�RU�IURP�a keyboard. When the write option is clicked, the data are added or updated in the tag memory, but DOVR�LQ�WKH�GDWDEDVH��7KH�¿HOG�WKDW�JXDUDQWHHV�WKDW�WKH� LQIRUPDWLRQ�VDYHG�LQ�WKH�5),'�WDJ� LV� WKH�VDPH�DV�LQ�WKH�GDWDEDVH�LV�WKH�XQLTXH�LGHQWL¿FDWLRQ�FRGH�of the tag. This number is read from the tag when any action is done on it and compared to the codes LGHQWLI\LQJ�DQ\�UHFRUG�LQ�WKH�GDWDEDVH��,I�DQ�8,'�LV�not present in the database, a new record is created.If a tag is deleted, the associated record in the database is not eliminated but marked as deleted.

All these actions are carried out almost LQVWDQWDQHRXVO\�� 7KH� VRIWZDUH� DOVR� YHUL¿HV� WKDW�the data to be recorded agree with the established format and sends an error message otherwise.

6. Conclusions

In this paper, a traceability system, based on 5),'�WHFKQRORJ\��LV�SUHVHQWHG��7KLV�FRQWURO�V\VWHP�has been specially designed to be integrated to the

UHVHDUFK� ZRUN� GHYHORSHG� DURXQG� WKH� 6HJHGD� VLWH�LQ� 6SDLQ�� WKRXJK� LW� FDQ� EH� DGDSWHG� WR� D� GL̆HUHQW�DUFKDHRORJLFDO� UHVHDUFK� JURXS� DQG� GL̆HUHQW�DUWHIDFWV��,I�WKH�DUWHIDFWV�DUH�ODUJH�HQRXJK��WKH�5),'�codes can be directly attached to them. The system prototype has been partially implemented and successfully tested in the reconstruction laboratory step. The whole prototype is going to be tried out in summer 2012.

7KH� XVH� RI� 5),'� WHFKQRORJ\� HDVHV� DQG�automates the process of data collection. The information can be updated simultaneously in the 5),'� WDJ� DQG� LQ� DQ� HOHFWURQLF� GDWDEDVH� ZLWKRXW�DPELJXLW\�� 7KH� VWRUDJH� FDSDELOLW\� RI� WKH� 5),'�tags makes it possibly to access to the relevant information of the artefacts without a network connection to the database. It is not possible with RWKHU� DXWRPDWLF� LGHQWL¿FDWLRQ� WHFKQRORJLHV� OLNH�FRGH�EDUV�� EHFDXVH� WKHLU� VWRUDJH� FDSDELOLW\� LV�YHU\� ORZ�� 'DWDPDWUL[� DQG� 4XLFN� 5HVSRQVH� FRGHV�have greater storage possibilities, but once the information code is created there is no possibility of adding or modifying the data saved. The memory of

Figure 8. Top Left. Basic actions of the RFID software. Figure 9. Left. After selecting the tracing option, the list of tags are shown on the screen. Figure 10. Top Right. Screen of data associated to an RFID tag.

CAA2012 Proceedings of the 40th Conference in Computer Applications and Quantitative Methods in Archaeology, Southampton, United Kingdom, 26-30 March 2012

64

DQ�5),'�WDJ�FDQ�EH�UHZULWWHQ�PRUH�WKDQ�D�KXQGUHG�times.

,QIRUPDWLRQ�WUDQVPLVVLRQ�E\�PHDQV�RI�UDGLR�wave signal does not require a perfect alignment EHWZHHQ� 5),'� WDJV� DQG� UHDGHUV�� $Q� 5),'� UHDGHU�placed at the exit door controls which elements OHDYH� RU� HQWHU� D� URRP�� $Q� 5),'� UHDGHU� FDQ� HYHQ�scan items inside a closed drawer or box, without the need to open it to see what is inside.

Finally, traceability implementation forces us to clarify and thoroughly understand what happens at every step in the process and what information LV�UHDOO\�UHOHYDQW��,W�KHOSV�WR�RSWLPL]H�WKH�FROOHFWLRQ�and management of data, reduces uncertainty DQG�PLVWDNHV��DQG�RSWLPL]HV�RXU�NQRZOHGJH�RI� WKH�present and past locations of the artefacts.

References

%XULOOR�� )�� ������ ³/D� &LXGDG� (VWDGR� 'H� 6HJHGD� ,�´� ,Q�Segeda y Su Contexto Histórico: Entre Catón y Nobilior

�����$O�����D�&����+RPHQDMH�D�$QWRQLR�%HOWUiQ�0DUWtQH]� HGLWHG� E\� )�� %XULOOR�� ��������� =DUDJR]D�� &HQWUR� GH�(VWXGLRV�&HOWLEpULFRV�GH�6HJHGD��

*ORYHU��%���DQG�+��%KDWW������� RFID Essentials (Theory LQ�3UDFWLFH���6HEDVWRSRO��2¶5HLOO\�0HGLD��,QF��

0DUWtQH]�0RUHQR�� -���3��*RQ]iOH]�0DUFpQ�� DQG�5��0RUD�7RUFDO��������³'DWD�0DWUL[��'0��&RGHV��$�7HFKQRORJLFDO�3URFHVV� IRU� WKH� 0DQDJHPHQW� RI� WKH� $UFKDHRORJLFDO�5HFRUG�´�Journal of Cultural Heritage������������������

3DUNV� &DQDGD�� ����� Parks Canada Archaeological Recording Manual: Excavations and Surveys. Version 1. 0. Quebeck:�3DUNV�&DQDGD��

6DQGV�� 5�� ����� Artefact Studies, Artefact Data and Information Technology: A Point in Time Review. 'XEOLQ��8&'�6FKRROV�RI�$UFKDHRORJ\��

6HJHGD� ������ ³6HJHGD� )RXQGDWLRQ� :HEVLWH�´� $FFHVVHG�-XO\��������KWWS���ZZZ�VHJHGD�QHW�