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virtual environments we propose a new conceptual so-
lution called normative virtual environments (NVE).
These are environments that provide a unified way
of controlling the interactions of participants through
normative regulation of these interactions and are ca-
pable of maintaining a causal connection (Maes and
Nardi, 1988) between all the existing environments.
This means that the state of any environment could be
changed through acting upon any other environment.
Further we present the architectural solution sup-
porting such causal connection. The proposed ap-
proach is quite general and has a wide range of ap-
plications from electronic markets to e-procurement
systems. For the clarity of this presentation, how-
ever, we limit the problem domain to fish markets.
The remainder of the paper is structured as follows.
Section 2 introduces the fish market domain. Sec-
tion 3 explains the concept of normative virtual en-
vironments and outlines the underlying technological
solution. Section 4 shows the implementation of the
fish market as a normative virtual environment. Fi-
nally, Section 5 presents some concluding remarks.
2 PROBLEM DOMAIN
In the Mediterranean fresh fish has been traditionally
sold through auction houses. There, fish is grouped
into sets of boxes (lots) and auctioned following the
Dutch protocol: price is progressively and quickly de-
creased by a small amount until a buyer submits a bid
or the price descent reaches a withdraw price.
Some contemporary fish markets automate their
selling methods via information technology. Figure 1
presents an example of such contemporary fish mar-
ket in Spain. Here the auction process is visualized on
the big electronic board. For each lot the board shows
the identification number of the product, type of prod-
uct, number of items in the lot and the current price.
The buyers are supplied with infrared devices that can
communicate with the main server. Pressing the “bid”
button on this device would stop the clock, finish the
auction and announce the buyer who has placed the
bid as the auction winner.
Figure 1: Contemporary Fish Market in Spain.
Even in such contemporary fish markets the pres-
ence of human buyers at the auction houses is still
necessary. This imposes two main barriers. First, it
restricts the potential buyers to those present in the
auction house. Second, it makes the participation in
several auctions simultaneously costly, as companies
have to send a representative to each one. The elim-
ination of such limitations would be very profitable
for both buyers and sellers. Increasing the number of
buyers makes the market more competitive and thus
increases the buying price to the benefit of sellers. It
also permits the participation of buyers without inter-
mediaries saving costs to the buyers. Next, we outline
the normative virtual environments approach offering
a general solution for eliminating these constraints.
3 NVE
The need for remote participation in fish markets was
expressed by the MASFIT project (Cun
´
ı et al., 2004),
which suggests using normative multiagent systems
for accomplishing this task. In particular, the partic-
ipation of buyers in fish market auctions is mediated
by a trusted third party called the electronic institu-
tion. An electronic institution formalizes the rules of
the fish market environment and establishes what the
participants are permitted and forbidden to do.
Such rules include the roles the participants can
play, the activities each role can engage into, the in-
teraction protocols associated to each of the activities
and a set of actions that can be performed. The tar-
get environment is separated into a number of logi-
cal groups of activities (scenes). Scenes are intercon-
nected to form a network that represents sequences
of activities, concurrency of activities or dependen-
cies among them. Only participants playing partic-
ular roles are admitted to a given scene, where they
should follow the interaction protocol specified for
the scene. Once the rules associated with an Elec-
tronic Institution are formalized, a software compo-
nent called AMELI can be used to launch the institu-
tion, let participants join it and communicate within
and will maintain the correct institutional state.
The MASFIT project wasn’t focused on integrat-
ing physical and virtual environments, instead it de-
veloped the mechanisms for software agents to par-
ticipate in a fish market simulation with similar con-
ditions as the humans do in the physical world. In our
approach we follow the path taken by the MASFIT
project for consistent integration of the virtual end
physical environments. Next, we present our solution
to extending the MASFIT approach.
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