Mes: diciembre 2009

A Trust Aggregation Engine that Uses Contextual Information
Joana Urbano

Enhacing traditional aggregation approaches by the inclusion of dynamics and being situation-aware (context).

Dynamics, based on Hysteresis of Trust and Betrayal (Straker, 2008), introducing 3 properties as asymmetry, maturity and distinguishable past. Thier model is called SinAlpha. Asymmetry penalizes intermittent behav., maturity avoids selection with few evidences and distiguishably prevents fast forgiveness. But the sin approach is not better than the linear model (experimentally).

Situation-aware is covered by contextual fitness. It is something very similar to CBR: clustering, stereotype extraction, analysis of similarity. Interestng for me: Multidimensional context representation for situational trust (Rehak, Gregor & Pechoucek, 2006). To do: deal with newcomers (first-encounter)

Preliminary Results on Reputation Systems: Balancing Quantity and Quality
Jonathan Ben-Naim

Agents in a network with a ranking that models reputation. A global measure (untractable for very large open systems as web). Two axioms: transitivity and strict transitiviy (good as first approach, but it can not be generalized). They refines the values in different interactions. What does it happend when there are loops? A lot of things to explain: ‘random’ initial ranking that he promises is not affecting to the final result (I can’t believe this), no weight/importance, the use of group size (stricti trans.) is questionable….

An Interaction-oriented Model of Trust Alignment
Andrew Koster

Well, I’ve seen this a lot of times: how to align trust concepts. Particularly, I prefer to have an standard on this part. Because we can continue with that: for example, ACL; why can’t we align ACL ontologies so the agents can speack in any language? In this case: agents share the same sintactis (about trust) and the semantics has to be aligned (what does it means to have a 0.8 confidence?) Implemented using inductive llogic programming (scalability?)

Supplier performance in a Digital Ecosystem
Angela Fabregues

Deals with partnership selection in cases where negotiation/argumentation is involved.

(Inciso: OMG bolitas paseándose por la pantalla, a DocThreeC le encantará esta plantilla ¿se lo digo? luego nos torturará).

To define the model of trust she begins with the ontology, similarity, expectations (see the invited talk of Carles Sierra this morning). By using past experiences, the probab. distribution of expected observation is modified. So, at the end, you do not take into accout the information about the exact object, but the similar ones too.

(otro inciso: ¡qué garrillas tiene la chica de las traspas! parece Ana Obregón :-D)

She continues explainig how the trust value is calculated using all these things and a bit (quickly) about similarity.

On Norm Internalization. A Position Paper
Daniel Villatoro (as guess star) in behalf of Rosaria Conte

How agents internalize existing norms and incorporates them to their behavior. He begins talking about goal internalization. At the beginnig, you behav. is directed by norms, but when yo asimilated them then you behaves in that way not to avoid a punishment, but because you want to behave in that way (for example, to stop when light is red in a semaphore). Too fast to listen and to write at the same time (you know, I’m a man), but it is a very interesting thing and I think that is related with adaptive organizations. I have to read the paper this this idea on mind. An intertesting point: urgency is a factor that affects to the speed at which intentions are internalized.

It is integrated with EMIL-A (BDI), N-Bel -> N-Goal -> N-Intentions that are Internalized as a conformed behav. A comment: this work is about people, not artificial agents.

Tags: eumas09, trust, reputation, dynamics, context,

On the design of mWater: a case study for Agreement Technologies
Pablo Noriega

About how to deal with water problems, involving many stakeholder with conflicting interests. This problem is modelled using electronic institutions. My comment: I think that is importan to consider more general works. I particularly like the papers about complex social ecological systems (Ostrom 2009 and Meizen-Dick 2007 ) which combines the environment, the resources, the users and the institutions and their relationships in a complete model. eInstitutions are very useful to model the institutional part (administrations, goverment…), but a more open environment (Thomas) is needed to take into account individual users and their social relationships to create a self-adaptive subsystem. I guess that this is the correct direction to deal with this problem. The vision that Carlos, Alberto and myself propose with consensus networks is just another point of view, but all of them are important and they need to be integrated.

Detecting Anomalies in Unmanned Vehicles Using the Mahalanobis Distance
Raz Lin

A model-free method based on statistical techniques to detect anomalies so that they can be corrected on time. They apply Mahalanobis distance (it sounds to me; i think that Alberto talked us about this for consensus networks; I have to check it). Using this distance eliminates the problems that appears in multidimensional data for euclidean distances. THe problem: it does not work well with qualitative changes (even if a partial order can be artificially defined?). An you’re losing a lot of domain dependent knowledge that can be useful!!

Dynamic ontology co-construction based on adaptive multi-agent technology
Sellami Zied

A tool to help ontologists to create ontologies (Dynamo project  A bit confusing: there is another dynamo for ontologies)

Tags: eumas09, agent, application, mwater, vehicles, ontology

Invited talk by Carles Sierra

The overview: beginning from individual opinion, how it is transformed into group opinion to achieve some reputation. Reputation is actually a grupal opinion about someone or something.

The example: Liquid publishing, about how people change their opinion by arguieng and considering reputation (the example is about paper review for a conference). The reputation of author, reviewers, the paper or the conference itself are considered.

First step: forming individual opinions. Agent receives messages that contribute to agent’s knowledge creating a distribution about the quality (or the true value) of the predicate. And this quality decays with time, having a decay limit distribution. This process (updating information and decaying with time) is reactive reasoning (giving formula about all these things). But we can have two types of opinion: verifiable (tomorrow will rain) and unverifiable (Earth will exist in 1 million years).

Second step: To structure the knowledge (as we organize sections in a paper). So the opinions can be given about each one of the identified elements and these opinions can be used to create a reputation value. So opinions are associated to nodes in the structure.

With that, entering in the third step: how group opinion are formed. To do that, (i) a language to share opinions, (ii) distances about opinions and (iii) methods to aggregate opinions are needed. So we are looking for a function \(\gamma\) that summarizes the group opinion. About the language, we can inform opinions (somehow a subjective thing) and experiences (objective facts). About getting information, citations can be good, but opinions can be even better (problem with ‘the rich get richer), and this can be done using distances between distributions: (i) by calculating how similar two functions are, (ii) calculating the distances between them (EMD)-not euclidean for opinions- Explaining different methods to combine opinions. Something interesting: reputation labels; inexorable, predetermination, persuasiveness, compliance, dogmatic and adherence that describe the position of an agent with respect to the opinion ofa group. BUt individuals have social relationships and this information ca be also taken into account.

So, to summarize:

• reputation is becoming crucial for all sort of web-related applications
• current model ignore the structure of the knowledge, as social relations
• integrated models that deals with all these information (social, structural, dependence…) are required

Tags: eumas09, reputation, opinion, group, knowledge

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