Extending CARREL's architecture for agents to argue over the viability of a human organ

Extending CARREL’s Architecture for Agents to Argue over the Viability of a Human Organ P. Tolchinsky, U. Cort´es, J.C. Nieves and J. V´azquez-Salceda Universitat Polit`ecnica de Catalunya Abstract In this report we present an extension to CARREL’s architecture. CARREL is an agent-based organization designed to improve the overall transplant process. The proposed extension will enable CARREL agents to reason and deliberate over the viability of a human organ for transplantation. We believe that allowing this deliberation has the potential to augment the organ pool for transplantation and thus, reduce the disparity between demand for, and supply of, human organs for transplantation. 1 introduction Human organ transplantation constitutes the only effective therapy for many life-threatening diseases. However, while the increasing success of transplants has led to increase in demand, the lack of a concomitant increase in donor organ availability has led to a growing disparity between supply and demand. Hence, much research has focussed on definition and implementation of policies for increasing donor availability, identification of suitable recipients for organs, and procedures to increase the chances of successful transplantation. As a consequence of the success of transplantation and the increase in the demand for transplant operations, the human transplant coordinators are currently facing significant problems in dealing with the volume of work involved in the management of requests, assignation and distribution of tissues and organs. Given the constant progress in transplant-based therapies and the relative success of these therapies, the demand for organs and tissues is expected to raise even more. A review of the coordinator’s role and the difficulties faced is presented in [9]. Moreover, there is an increasing requirement for managing and processing vast and complex data, and accommodation of a complex set of, in some cases conflicting, national and international regulations and protocols governing exchange of organs and tissues. Hence, in [15] an agent-based architecture - CARREL - is proposed for managing the data to be processed in carrying out recipient selection, organ and tissue allocation, ensuring adherence to legislation, and following approved protocols and preparing delivery plans. In [14] we proposed a novel selection process of human organs for transplantation. We claimed this new process to have the potential to increase the 1 human organ pool for transplantation, i.e. to reduce the organ shortage for transplantation. Our thesis relays on the fact that, despite the scarcity of organs, a great number of organs available for transplantation are discarded as being deemed non-viable for that purpose. We described this proposed process in the CARREL system, and thus, we now formalize this extension. In this report we describe the extension of CARREL’s architecture in order to capture the new discarding process. Hence, in the next section we present the CARREL agent-based organization as it currently is. In section 3 we introduce the proposed human organ selection process and in section 4 we describe the formalization of the extended CARREL’s architecture. In section 5 we give our conclusions. 2 The Carrel Institution Since 1980 the number of transplant requests has been constantly increasing. As a consequence, the human transplant coordinators are currently facing significant problems in dealing with the volume of work involved in the management of requests, assignation and distribution of tissues and organs. With CARREL we intend to automate many of the task carried now a days by humans. Two aspects can be highlighted that make transplantation management a very complex issue: (i) the need to maximize the number of successful transplants due to the scarcity of donors (ii) the complexity of the donor/recipient matching due to the diversity and multiplicity of genetic factors involved in the response to the transplant. The CARREL System is intended to automate many of the tasks that now a days are carried out by human beings. CARREL’s design takes the Spanish and Catalan transplant organizations as references, both known to be examples of best practice. Hence, they constitute viable physical institutions on which to base electronic ones. The Spanish organizational model has two levels of action: Intra-hospital: Where the role of hospital Transplant Coordinator was created to improve the coordination of all the people working at any step of the donor procurement, allocation and transplantation process. Inter-hospital: Where an intermediary organization, the Organitzaci´o CATalana de Trasplantaments [11](OCATT) for Catalonia, Organizaci´on Nacional de Transplantes [12] (ONT) for the whole of Spain was created to improve the communication and coordination of all the participating health-care transplant organizations, namely hospitals and tissue banks. Fig. 1 depicts the inter-hospital level managed by CARREL in which we can identify the entities that interact with the CARREL system. Each TB denotes a tissue bank, each UCTx denotes a transplant coordination unit, the agency that represents a hospital member of CARREL. The ONT and OCATT denote the organ transplantation organizations that own the agent platform and act as observers. 2 Hospitals without a Tissue Bank (TB) Hospitals (UCTx) with TB Figure 1: CARREL’s environment. We make it a requirement in our model that all hospitals, even the ones that own a tissue bank, will make their requests through CARREL in order to ensure an acceptable distribution of tissues and to ease the tracking of all tissues from extraction to implant, in the same manner as ONT and OCATT require for organs. The role of the CARREL Institution can be summarized in terms of following the tasks: T1 to make sure that all the agents which enter into the institution behave properly (that is, that they follow the behavioral norms). T2 to be up to date about all the available pieces in the Tissue Banks, and all the recipients that are registered in the waiting lists. T3 to check that all hospitals and tissue banks fulfill all the requirements needed to interact with CARREL. T4 to take care of the fulfillment of the commitments undertaken inside the CARREL system. T5 to coordinate the piece delivery from one facility to another. T6 to register all incidents relating to a particular piece. A hospital becomes a member of the CARREL institution in order to make use of the services provided. In doing so, they accept to respect the norms that rule the interaction inside CARREL. Some of these norms are: N1 All organ offers and tissue requests should be done through the CARREL institution. N2 Hospitals must accept the outcomes of the negotiation (assignation) process. 3 N3 Hospitals receiving an organ or tissue from CARREL must update the institution with any relevant event related to these organs and tissues. Each hospital member of CARREL is represented by the Transplant Coordination Unit (UCTx) that manages the intra-hospital level. Each UCTx aim is to successfully culminate any organ and tissue procurement, extraction and implantation process. Each UCTx is modelled as an agency, the roles the different agents play in this agency are presented in [4]. In this report we only identify agents in UCTx that can enter to the CARREL institution (section 4). Before addressing the CARREL formalization (section 4) we introduce the human organ discarding process, motivating the extension to the current agentbased organization’s architecture. 3 Introducing the human organ discarding process When a potential donor is detected, a Transplant Coordinator has to determine which of the donor’s transplantable organs are viable for that purpose. While the organs deemed as viable are offered for transplantation, the organs deemed as non-viable are not, thus, preventing all the Transplant Units from considering this organ transplantation to any of the potential recipients under their responsibility. Currently in Catalonia, a world leader in transplantation, between 15 and 20 percent of the livers, 20% of the kidneys, 60% of the hearts, 85% of the lungs and 95% of the pancreas, from donors that were detected, are discarded [OCATT]. Given the scarcity of human organs for transplantation we believe no further motivation is needed for proposing an alternative human organ discarding process. The proposed discarding process aims to reduce the discarding organs by enabling Transplant Units take part in the decision to whether an organ is viable or not for their patient prior to the organ offer. Two aspects underpins the proposed process: i)organs are rarely non-viable or ideal per se. The term ideal organ should imply an integral concept that involves donor and recipient characteristics and all the procedure performances between both [8]. ii) Different qualified professionals have different opinion on the viability for transplantation of a human organ for transplantation. Namely different physicians follow different human organ acceptability criteria. In the following subsection we describe the current discarding process to then describe the alternative process 3.1 The Current Human Organ Discarding Process From the moment a potential donor is detected until the moment his organs are transplanted there is a filtering process in which the different stakeholders may decline to transplant or to offer for transplantation each of the donors organs considered transplantable, viz. heart, lungs, liver, pancreas and kidneys (in fact, we only consider solid organs). 4 The process begins when a Transplant Coordinator (TC) detects a potential donor, in which case, after properly analyzing his characteristics, she informs the OCATT, assuming the TC is located in Catalonia, about the organs she considers viable for transplantation. If the TC is aware of any potential recipient that could match one of the donors organs, she may consult or even delegate that decision to the professionals in the Transplant Unit (TU) who are responsible of that potential recipient. This should be done before informing the OCATT and it normally happens when the recipient and the donor are located in the same hospital. If the TC considers the organ as viable but no match for the given organ is found among the potential recipients in the waiting lists of Catalonia, the OCATT will offer the organ to the ONT. Otherwise, if a recipient is found, the allocation process takes place and the organ is offered to a Catalan TU that may or may not accept the organ1. If refused, the organ will be offered to a different TU until final acceptance or refusal. The TU that accepts the organ has the right to discard it after or during the extraction operation, in which case it is very unlikely to have the organ transplanted. If no TU accepts the organ, it is offered to the ONT. When an organ is offered to the ONT, a similar process takes place, this time however embracing Spain and not only Catalonia. In case the organ could not be allocated, the OCATT will offer the organ to transplant organizations in Europe. If these organizations fail to allocate the organ, the OCATT will then offer it in Asia. However, this last step hardly ever occurs. If every organization fails to allocate the organ, the organ will not be retrieved from the donor. 3.2 The Alternative Human Organ Discarding Process In order to reduce the number of human organ discards we propose an alternative discarding process in which the organs initially deemed as non-viable by a TC can also have the opportunity to end up being transplanted. This is done by enabling the Transplant Units to take active part in the human organ decision making over the viability of an organ. Namely, in this proposed discarding process, the Transplant Coordinator will offer not only the organs deemed as viable but also the organs deemed as non-viable. In this occasion the organ offers made by a TC must be followed by the arguments claiming the viability or non-viability of the offered organ. These arguments can then be counterargued by a TU that disagrees with the TC assessment. In particular, an organ deemed as non-viable by a TC can be claimed to be viable by a TU that if providing valid reasons for transplanting the organ, this organ should not be discarded before it is offered to this TU. Given that each TU can argue over the viability or non-viability of the human organ, after the argument evaluation, to each TU the organ is labelled as either viable or non-viable. Figure 2 depicts both the flow of the current discarding process and the proposed one. 1It is worth mentioning that at this stage the offered organ has not yet been extracted. It is after accepting it that a Transplant Unit may extract the organ from the donor and make a more complete evaluation 5 Potential Donor Potential Donor Potential Donor Allocation Process ONT Refuse When Offered All the TU Refused the Organ Discard Transplant Coordinator OCATT Transplant Transplant Unit Transplant UnitTransplant Unit Transplant Unit Offer Discard Transplant Offer An organ will be offered to only one Transplan Unit at a time, If a TU refuse the organ, it will then be offered to the following TU. viable organ non-viable organ Transplant Unit consult or delegate refuse Detected Transplant Unit Potential Donor Potential Donor Potential Donor Transplant Coordinator Allocation Process Recipient Agent Transplant Unit Transplant Unit Transplant Unit OCATT ONT Transplant Unit Transplant Unit Offer Refuse When Offered All the TU Refused the Organ when Offered Or Labeled it as Non-Viable Discard Transplant Discard Detected Discard Transplant Transplant Unit N N V NVVN V Recipient AgentTransplant UnitRecipient Agent Recipient Agent Recipient Agent Recipient Agent Recipient Agent Recipient Agent Offer Transplant Unit Transplant Unit Transplant Unit Transplant Unit Transplant Unit Transplant Unit Transplant Unit Transplant Unit Recipient Agent Transplant UnitRecipient Agent Transplant UnitRecipient Agent Case 1: The organ considered as Viable by the TC Case 2: The organ considered as Non-Viable by the TC Phase in which the organ labelling take place An organ is offered to one TU at a time, and only to TU to which the organ was labelled as viable. V: Organ labelled as Viable N: Organ labelled as Non-Viable Transplant Unit Transplant Unit Transplant Unit a) b) Figure 2: Flow of the Current Human Organ Discarding Process a) and the Flow of the Proposed Organ Discarding Process b). As we can see, in b) organs initially deemed as non-viable by the Transplant Coordinator (dashed lines) can end up being offered to a Transplant Unit and subsequently being transplanted. Note that, in both a) and b) an organ is not offered in parallel to the TUs but sequentially. It is only after a TU refuses the organ that it is offered to the following TU. In [14] and [10] a more detailed description of the proposed process is given, also we describe the agents’s argumentation process. In these works when framing the scenario within CARREL, for readability reasons we named Transplant Coordinator Agent (T CAi) the agent that carries the TC arguments (also named Donor Agent in [10]), and Transplant Unit Agent (TUAj) the agent that carries the TU arguments (also named Recipient Agent in [10]). The agent that evaluated these arguments was named Mediator Agent and the agent playing the role of the Transplant Organizations was named Organization Agent (see figure 3). In the actual extension of CARREL the tasks carried by these agents are carried out by diverse agents that in some cases carry out other tasks than the ones described in [3], [14] and [10]. These agents and in general the CARREL’s extended architecture are described in the following section. 6 UCTX UCT2 UCT1 UCT3 OA ONT OCATT CARREL Transplant Organization Room Evaluation Room MA OA MA Transplant Coordinator Agent Mediator Agent TCA2 TCA3 TCAX TCA1 TUA1 TUA2 TUA3 TUAX TCA1 TCA1TUAj TCAX OA OCATT Agent (or another Transplant Organization Agent) Transplant Unit Agent TUAX Figure 3: The CARREL System managing the human organ discarding process 4 Formalizing CARREL’s extended architecture CARREL is formalized as an electronic institution in which the interactions among a group of agents are governed by a set of norms expressed in the ISLANDER specification language [5]; CARREL can be regarded as a type of dialogical system where all the interactions are compositions of message exchanges, or illocutions, structured through agent group meetings called scenes or rooms. Each agent can be associated with one or more roles, and these roles define the rooms the agent can enter and the protocols it should follow. Figure 4 depicts CARREL’s performative structure, in which nodes denote the scenes which are connected by arcs that denote the different paths the agent can take. The arcs are labelled with the agent’ roles that can follow a give path. Arcs are also labelled with either a new or 1, the former indicates that the agent that enters the scene via that arc creates the scene, whereas the later denote that the agents entering via that arc are constraint to enter to a single instance of that scene. On the upper right corner of figure 4 we can identify an elliptical node that stands for a CARREL platform. Although it does not complies with the ISLANDER’s notation we use it for readability purposes to denote that agents can be headed to a different CARREL platform (we address this in section 4.2.3). In figure 4 we can identify several scenes or meeting rooms in a broad view, each scene can be defined as follows: Reception Room: is the scene where all the external agents should identify themselves in order to be assigned the roles they are authorized to play. If these agents are carrying either a request for a tissue or an offer of an organ, then this information is checked to make sure that it is well-formed. Consultation Room: is the scene where the institution is updated about any event or incident related to a piece. Agents coming from tissue banks 7 consultation room output root transplant organization room evaluation room organ exchange room reception room confirmation room tissue exchange room organ exchange room tissue exchange room evaluation room CARREL y:hf|z:hc w:hi|v:tb x:orm x:cfrm x:trm y:hf y:hf y:hf y:hf y:hf y:hf y:hf x:erm x:torm x:crm w:hi|v:tb w:hi|v:tb w:hi|v:tb y:hf y:hf y:hf z:hc z:hc z:hc y:hf|z:hc y:hf|z:hc w:hi|v:tb x:rrm y:hf y:hf x:rrm 1 x:torm new 1 new 1 1 1 1 11 1 1 1 1 1 1 1 1 new new new new new y:hf y:hf w:hi|v:tb y:hf Figure 4: CARREL’s performative structure. should update the institution about tissue availability, while agents coming from hospitals should update the institution about the waiting lists and also inform it about the reception of all pieces (organs or tissues) they have received, the transplant operation and the condition of recipients. In this extension, the hospital agents also provides the reasons for any failure in the transplant process. Transplant Organization Room: is the scene where the organ offers are directed to the suitable recipients, first within a CARREL platform and if no suitable recipient is found for that organ, the organ is offered in other CARREL platform. If no suitable recipient is found in any CARREL platform, the organ is discarded. Evaluation Room: is the scene where the agent’s arguments for the viability or non-viability of a given organ are evaluated. Exchange Room: is the scene where assignation of pieces takes place. In fact, there are specific exchange rooms for tissue requests (Tissue Exchange Room) and for organ offers (Organ Exchange Room). Confirmation Room: is the scene where the provisional assignments made at the exchange rooms are confirmed, whereafter a delivery plan is constructed, or cancelled, because a new request of higher priority has arrived. The agents that can be identified in figure 4 are of two types, internal agents and external agents. The former are CARREL agents that manage each of the 8 scenes depicted in the figure. Whereas the later are agents that belong to either UCTx or they represent a tissue bank. In more detail, the external agents are: Hospital Finder Agent (hf): agents sent by the hospitals with a request for a potential recipient for a given organ2or a tissue request. If the agent is searching for a tissue, it carries the potential recipients’ characteristics as well as the preferences on the characteristics of the requested tissue. CARREL must then find the most appropriate tissue among the Tissue Banks. Whereas agents offering an organ carry the donor’s and organ’s characteristics as well a set of arguments, these arguments represent the Transplant Coordinator’s belief over the viability of the offered organ. CARREL must then find the most appropriate recipient among the waiting lists. Hospital Contact Agent (hc): agents from certain hospitals that are contacted by the institution when an organ is offered that matches the characteristics of recipients on these hospitals’ waiting lists. The agents then enter to the institution in order to take part in the allocation process of the offered organ. hc, in this extension, can argue over the viability of the organs they are offered. Hospital Information Agent (hi): agents sent by hospitals to keep the CARREL system updated about any event related to a piece or the state of the waiting lists. If a failure in the transplant process occurs they must provide CARREL with the reasons of that failure. They can also perform queries on the CARREL’s database and knowledge base. Tissue bank notifier (tb): agents sent by tissue banks in order to update CARREL about tissue availability. And the internal agents: Reception Room Manager (rrm): manager of the Reception Room scene. Thus, a rrm agent is an internal agent responsible of the external agents access to CARREL. Tissue Exchange Room Manager (trm): manager of a Tissue Exchange Room scene. trms manage the provisional tissue assignations to external agents, in particular to hf agents. Organ Exchange Room Manager (orm): manager of a Organ Exchange Room scene. orms manages the provisional organ assignations to external agents, in particular to hc agents. Confirmation Room Manager (cfrm): manager of the Confirmation Room scene. The provisional assignations made by a trm or orm agent are made effective by a cfrm agent 2When a Hospital Finder Agent offers a human organ for transplantation, it can be regarded as searching for an appropriate recipient for the given organ, i.e. it enters to CARREL with a request potential recipient. 9 Msg]Illocution 24 (request (!x erm) (hc) (call for recipient !id petition ?time for availability ?piece type (?piece parameters) (?info donor) (?arguments is viable))) 25 (inform (?z hc) (!x erm) (call answer !id petition ?id recipient ?id hospital (?info recipient) (?arguments is viable))) 26a (inform (!x erm) (!z hc) (organ viability !id recipient non-viable (?reason))) 26b (inform (!x erm) (!z hc) (organ viability !id recipient viable (?reason))) 27 (request (!x erm) (all) (allin)) 28 !evaluation timeout 29 (request (!x erm) (all) (recipient not found reason !id petition)) 30 (request (?x erm) (all) (recipient found !id petition (?viable hc))) Figure 11: The illocutions for the Evaluation Room W0 +hf 24 W1 +hc W3 W2 W4 -hf -hc W5 -hf -hc 25 26a,26b 27,28 29 30 Figure 12: Conversation graph for the Evaluation room 16 Msg]Illocution 31 (query-if (?x orm) (?z hc) (organ offer accept ?id petition)) 32 (inform (!z hc) (!x orm) (organ offer !id petition refuse ?reason)) 33 (inform (!z hc) (!x orm) (organ offer !id petition accept)) 34 (inform (!x orm) (all) (recipient found !id petition !id recipient !id hospital)) 35 (inform (!x orm) (all) (recipient not found reason ?id petition))) Figure 13: The illocutions for the Organ Exchange Room W0 +hf +hc W1 31 33 W2 -hc W4 -hf -hc W5 -hf -hc 31 32 35 W3 34 Figure 14: Conversation graph for the Organ Exchange room the institution’s call (message 27) or when the evaluation time is out (message 28), if no recipient was found for the offered organ, hf is headed again to the Transplant Organization Room (message 29). Otherwise, the hf and all the hc to whom the organ was labelled as viable are directed to the Organ Exchange Room (message 30). 4.1.5 Organ Exchange Room After the agents’ arguments are evaluated in the Evaluation Room a prioritized queue with the hc that have labelled the organ as viable is available for the agents playing the Organ Exchange Room Manager role orm. On the basis of this prioritized queue orm will attempt to arrive to a provisional organ assignation to a hc agent. Thus, following the queue order, orm queries each hc whether they accept or reject the offered organ (see fig. 13 for the scene protocol). This is done as long as the hc agents refuse the organ (message 32). Once a hc accepts the offered organ (message 33) this agent and the hf are headed to 17 the Confirmation Room (message 34). If no potential recipient is found for the offered organ, hf is directed to the Transplant Organization Room (message 35). 4.1.6 Tissue Exchange Room The Tissue Exchange Room is the place where negotiation over tissues is performed. The protocol of this scene is shown in figure 15: hf asks the scene manager for tissue offers (tissues matching the requirements included in their petition) (message 36). Then the scene manager provides a list of available tissues (message 37) that is evaluated by the external agent hf (message 38). With this information the scene manager can make a provisional assignment and solve collisions (two agents interested in the same piece). When this provisional assignment is delivered (message 39) hf exits the scene to go to the Confirmation Room represented by state W4. There is an alternative path for the case when there are no available pieces matching the requirements described in the petition (message 37 with null list). In this case hf requests an exit permission from the institution (message 40, exit state W6), including the reason for leaving. The reason provided is recorded in the institution logs to form an audit trail for the relevant authorities to inspect. For further information about this negotiation process see [2]. 4.1.7 Confirmation Room In the Confirmation Room scene, the provisional assignments made in a Tissue Exchange Room or an Organ Exchange Room are either confirmed or withdrawn. Figure 17 shows the protocol of this scene: the agent can analyze the assigned piece data and then accept or refuse it (messages 42a or 42b). If an agent (either hc or hf) accepts the piece and no higher-priority requests appear during a certain time window then the provisional assignment is confirmed and a delivery plan is given to the agent (messages 43a or 43b), and then it exits the CARREL system (exit state W4). When there is a request with higher priority that needs the piece provisionally assigned to an agent a conflict arises. To solve the conflict the scene manager notifies the agent that the assignment has been withdrawn (message 44a or 44b) and that he is then entitled to a fresh request for another piece in the case of the hf requesting a tissue, if available, (message 45) to be negotiated again in the Exchange Room whence it came. hc exits the institution if the organ assignation could not be completed. 4.2 CARREL overview The presented extension to the CARREL architecture enables to support the new requirements raised with the proposal of incorporating into CARREL the discarding process presented in [14]. Thus, the arguments representing the beliefs of a Transplant Coordinator and a Transplant Unit about the viability of the offered organ can now be managed within the CARREL System, given that these arguments can know be carried by hf and hc, respectively and evaluated 18 Msg]Illocution 36 (query-if (?y hf) (?x term) (offer list ?id petition)) 37 (inform (!x term) (!y hf) (offer list !id petition (list (?id piece1 ?info piece1) ...(?id piecen ?info piecen))) 38 (inform (!y hf) (!x term) (weighted list !id petition (list (!id piece1 ?weight) ... (!id piece1 ?weight))) 39 (query-if (!x term) (!y hf) (piece offer (?id petition ?id piece ?cost estimation))) 40 (request (!x hf) (u im) (exit ?exit reason)) Figure 15: The illocutions for the Tissue Exchange Room W0 +hf W1 36 37a W6 -hf 37b W4 -hf W2 W3 W5 38 39 40 Figure 16: Conversation graph for the Tissue Exchange room 19 Msg]Illocution 41a (request (!y hf ) (u im) (exit ?exit reason) 41b (request (!z hc ) (u im) (exit ?exit reason) 42a (inform (?y hf ) (?x cfrm) (piece eval ?id petition ?id piece ?accepted)) 42b (inform (?z hc) (?x cfrm) (piece eval ?id petition ?id piece ?accepted)) 43a (inform (!x cfrm) (!y hf) (piece delivery ?id petition ?id hospital ?id tissue bank ?delivery plan)) 43b (inform (!x cfrm) (!z hc) (piece delivery ?id petition ?id hospital donor ?id hospital recipient ?delivery plan)) 44a (inform (!x cfrm) (!y hf ) (piece reassigned exception ?id petition ?id piece ?reassignment reason)) 44b (inform (!x cfrm) (!z hc) (piece reassigned exception ?id petition ?id piece ?reassignment reason)) 45 (query-if (?y hf) (?x cfrm) (another offer list ?id petition)) Figure 17: Illocutions for the Confirmation room W0 +hf +hc W3 41a,41b 43a,43b W2 -hf -hc 44a W5 45 W1 W4 -hf -hc W6 -hf 42a(accepted) 42a(refused) 44b 44b 44a 42b(accepted) 42b(refused) Figure 18: Conversation graph for the Confirmation room 20 (define-performative-structure carr-performative-structure as scenes= ((root root-scene) ; declare the (r-room reception-room-scene) ; scenes comprising (te-room tissue-exchange-room-scene list ; the institution (e-room evaluation--room-scene list) (to-room transplant-organization-room-scene) (oe-room organ-exchange-room-scene list) (cf-room confirmation-room-scene) (cs-room consultation-room-scene) (output output-scene) ) transitions = ; set up the transitions ((createR-room AND) (toR-room OR) ... connections = ; and set up the connections ((root toR-room (((x hf)))(((y hc)))(((z hi)))(((w tb)))) ... initial-scene = root final-scene = output ) (define-dialogic-framework carr-dialogic-framework as ontology = carr-ontology representation-language = first-order-logic illocutionary-particles = (......) external-roles = (hf, hc, hi, tb) ; list all the roles internal-roles = (im, rrm, trm, orm, cfrm, crm, torm, erm) ; that participating role-hierarchy = ((im rrm) (im trm) (im orm) ; agents may play and (im cfrm) (im crm) (im torm) (im erm) ; how the roles are related ) ; to one another social-structure = ((im > rrm) (im > trm)...(rrm > tb)) ) (define-scene e-room as ; roles = (erm hf hc) ; contained in a particular scene scene-dialogic-framework = e-room-df ; specifying which roles may participate state = (W0 W1 W2 W3 W4 W5) ; the rest is just a textual initial-state = W0 ; representation of a finite state final-states = (W4 W5) ; machine access-state = ((erm (W0)) (hf (W0)) (hc (W1))) exit-states = ((trm (W4 W5)) (hf (W4 W5)) (hf (W4 W5))) agents-per-role = ((1 <= trm <= 1) (1 <= hf <= 1) (0 <= hc)) conections = ; transition labels are speech acts ((W0 W1 (request (?x erm) (hc) (call_for_recipient ?id_petition ?time_for_availability ?piece_type (?piece_parameters) (?info_donor)(?arguments_is_viable))))) (W1 W2 (inform (?z hc) (!x erm) (call_answer offer_list ?id_recipient !id_petition ?id_hospital (?info_recipient) (?arguments_is_viable)))) ... (W3 W5 (request (!x erm) (all) (recipient_found !id_petition) )) ) ) Figure 19: A code fragment of the CARREL System’s specification 21 in the Evaluation Room. Note that the hi can also provide arguments, these arguments represent the Transplant Unit’s justification to any failure in the transplant process and are carried by the hi into the Consultation Room. In figure 20 we can identify the agents that conform the CARREL agent-based organization. The different arrow types in the figure denote different interactions. The ACKB, that stands for Acceptability Criteria Knowledge Base, can be regarded as the knowledge base that capture the valid criteria on which a decision to whether an organ is viable or not can be taken.The CBRe, that stands for Case-Based Reasoning Engine, evaluates the validity of the arguments used by the agents. Both ACKB and CBRe are described in [14]. We are currently designing both ACKB and CBRe from which the Criteria Agent (see fig. 20) can derive the validity of the given criteria for accepting or rejecting a human organ used by the external agents. The agents with a scene managing role interact with the external agents, whereas agents playing the roles of Planner Agent, Data Base Agent or Criteria Agent support the former providing them with the required information, such as delivery plans, or a potential recipient’s waiting lists. These agents are also responsible of updating the bases (Data Base, Case-Based and the Acceptability Criteria Knowledge Base) when required. DB CBRe ACKB Confirmation Agent Planner Agent Reception Agent Data Base Agent Criteria Agent Consultation Agent Organization Agent Evaluation Agent Organ Exchange Agent Tissue Exchange Agent Institution Manager Interface Institution Manager Agent Institution Manager Figure 20: The Carrel agent based Organization 22 5 Conclusions CARREL is an agent-based organization designed to improve the overall transplantation process. Previous concerns in the formalization of CARREL were related to normative aspects. Namely, how to capture all the legal issues related to the transplant process when certain tasks are no longer carried out by humans but are automated. The extension to CARREL architecture described in this report stem from another concern, the ability of the software agents to reason about the medical criteria. In particular, we center our efforts on the ability of the software agents to reason about the human organ acceptability criteria, given that it is a particularly ill-defined problem and at the same time it is a critical issue within the human organ transplantation domain (see [1]). Thus, the extension of CARREL’s architecture described in this report will enable agents to argue over the viability of a human organ. The integration to CARREL of our work presented in [14] is still work in progress given that components such as the ACKB and CBRe are yet to be designed. Also the formalization of the CARREL federation, already mentioned in [13], has not yet been accomplished. Hence, remaining to be addressed in forthcoming work Acknowledgments This report was supported in part by the Grant FP6- IST-002307 (ASPIC). References [1] F. Caballero. Ampliaci´on del los criterios de aceptaci´on de los donantes de ´organos. Resultados a corto y largo plazo de transplantes realizados con injertos de donantes fallecidos por intoxicaci´on aguda. PhD thesis, Universidad Aut´onoma de Barcelona, 2005. [2] U. Cort´es, A. L´opez-Navidad, J. V´azquez-Salceda, A. V´azquez, D. Busquets, M. Nicol´as, S. Lopes, F. V´azquez, and F. Caballero. Carrel: An agent mediated institution for the exchange of human tissues among hospitals for transplantation. In 3er Congr´es Catal`a d’Intel.ligencia Artificial, pages 15–22. ACIA, 2000. [3] U. Cort´es, P. Tolchinsky, J. C. Nieves, A. L´opez-Navidad, and F. Caballero. Arguing the discard of organs for transplantation in CARREL. In CATAI 2005, pages 93–105. 2005. [4] U. Cort´es, J. V´azquez-Salceda, A. L´opez-Navidad, and F. Caballero. UCTx: a multi-agent approach to model a transplant coordination unit. In Proceedings of the 3rd. Congr´es Catal`a dIntellig`encia Artificial, 2000. [5] M. Esteve. Electronic Institutions: from specification to development. PhD thesis, Universitat Polit`ecnica de Catalunya, 2003. [6] J. Fox and S. Das. Safe and Sound. AAAIPress/MIT Press, 1st edition, 1999. 23 [7] A. Lin. Integrating policy-driven role-based access control with common data secutiry architecture. Technical Report HPL-1999-59, HP Laboratories Bristol, 1999. [8] A. L´opez-Navidad and F. Caballero. Extended criteria for organ acceptance: Strategies for achieving organ safety and for increasing organ pool. Clin Transplant, Blackwell Munksgaard, 17:308–324, 2003. [9] A. L´opez-Navidad, P. Domingo, and M.A. Viedma. Professional characteristics of the transplant coordinator. In Transplantation Proceedings, number 29, pages 1607–1613. Elsevier Science Inc, 1997. [10] S. Modgil, P. Tolchinsky, and U. Cort´es. Towards formalising agent argumentation over the viability of human organs for transplantation. Submitted to the MICAI conference, 2005. [11] OCATT. Organitzaci´o Catalana de Transplantaments (OCATT). http://www10.gencat.net/catsalut/ocatt/en/htm/index.htm. [12] ONT. Organizaci´on Nacional de Transplantes. http://www.msc.es/ont. [13] J. V´azquez Salceda. The role of Norms and Electronic Institutions in Multi- Agent Systems applied to complex domains. The HarmonIA framework. PhD thesis, Universitat Polit`ecnica de Catalunya, 2003. [14] P. Tolchinsky, U. Cort´es, J.C. Nieves, F. Caballero, and A. L´opez-Navidad. Using arguing agents to increase the human organ pool for transplantation. In 3rd Workshop on Agents Applied in Health Care (IJCAI-05), 2005. Accepted. [15] J. V´azquez-Salceda, U. Cort´es, J. Padget, A. L´opez-Navidad, and F. Caballero. The organ allocation process: a natural extension of the CARREL Agent-Mediated Electronic Institution. AiCommunications, 3(16):153–165, 2003. 24