area. Therefore, we adopt norm approach, which is a
partial factor of decision making about the currently
environmental conditions, to reconcile contending
preferences from the different occupants. We
employ norms in two main tasks: 1) to assign the
priority to a particular occupant 2) to assign the
weight to normative goals and individual goals.
Whenever a room is occupied by more than one
person, we claim that a human being society, either
formal or informal, is set up, and leads to assigning
of role for each person in the society. For instance,
in a private area, such as an office room scenario, an
informal society is formed when anybody comes
into the room then the role of this scenario is
categorized into owner and visitor(s). On the other
hand, in a common area such as a meeting room, the
members of conference compose with a chairman, a
secretary, a president, a board of director etc. These
roles are considered as a formal role because it is
defined by the organizational structure in terms of a
hierarchical relationship. In a common room where
anyone takes a break for drinking, eating, relaxing
etc., an informal society occurs. Therefore, the
society is a lateral or peer-to-peer relationship. By
using a role concept, it will be adopted to classify
the different priority between particular occupants.
The high the occupant presents in the level of a
hierarchical relationship, the high the occupant gets
priority in the public area. Therefore, a relative
ordering on the values of occupants’ preferences is
created.
Norms represent what the members in society
ought to do, and their fulfilments can be seen as a
benefit of the overall system. However, in some
circumstances, individual goals conflict with the
norms. In a multi-occupant situation, each occupant
has the personal preferences that can be seen as the
individual desires. By contrast, the normative goals
are the certain environmental conditions that make
all occupants as comfort as possible. Therefore, two
steps of conflicting resolutions are needed. The first
step is to resolve conflict among the occupants for
finding the optimal preferences the make most
occupants feel comfortable. The optimal preferences
are evaluated by the system whether they fall in
which level: saving energy level or comfort level. If
the result falls in saving energy level then the second
step is not happen because the individual goals are
not conflict with the normative goals. In contrast, the
second step is initiated to resolve the conflict. In our
research, we adopt negotiation to reconcile the
conflict then a goal of negotiation is to maximize
occupant comfort and minimize energy
consumption.
2.3 The BDI Model and Norms
Norms, claimed by (Torre 2001), are used for
linking the gap between an agent level and a multi-
agent system level. This means that a role of norms
and obligations can support an agent society so
many previous researchers tried to enhance an
agent’s ability by proposing a novel agent model
that can make decision under norms: obligations,
permissions and prohibitions. Although BDI is the
most widely known model that is used to implement
an agent for individual and intentional decision
processes, this model was not been represented
nothing about the social aspects of agent being in the
multi-agent systems. However, the BDI model has
some limitation such as lacking of policy and norm
supporting ability then many researchers have
proposed the extended-BDI models for example;
extension of BDI model with norm (Dignum 1999),
Belief-Obligation-Intention-Desire (BOID) model
(Broersen, Dastani et al. 2001) ,normative agent
architecture (Lopez and Marquez 2004), EDA model
(Filipe 2000), and so on. These extending
architectures are the normative model addressing the
usage of norms and policies for reasoning and social
interacting. An agent that can reason about norms
and obligations is called a normative agent
(Verhagen 2000) or a deliberate normative agent
(Castelfranchi, Dignum et al. 1999). The deliberate
normative agent has explicit knowledge of the
enacted norms for reasoning, and can make a
decision whether to comply with norms or not in
some cases.
Broerson et al. (Broersen, Dastani et al. 2001)
have proposed BOID architecture that composes
with four basic components. The architecture
focuses on conflict resolution among informational
and motivational attitudes. The possible conflict is
classified into two types: internal and external
conflicts. The internal conflicts occur within beliefs,
obligations, intensions, and desires, and can be
categorized into four unary subtypes: B, O, I, D. The
external conflicts occurring between these
components can be distinguished into multi
subtypes: BO, BI, BD, OI, OD, ID, BOI, BOD, BID,
OID, BOID. The conflict resolution mechanism is
based on Thomason’s idea of prioritization which
can determine the type of an agent simultaneously.
The BOID architecture is discussed more detail in
(Broersen, Dastani et al. 2001). Lopez et al. (Lopez,
Luck et al. 2001; Lopez and Marquez 2004) have
proposed a framework representing the adoption of
norms towards the BDI agent. The authors present
an abstract normative agent architecture designed by
A MULTI-AGENT SYSTEM FOR INTELLIGENT BUILDING CONTROL - Norm Approach
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