=Paper= {{Paper |id=Vol-2215/paper16 |storemode=property |title=Semantic-based Social Intelligence through Multi-Agent Systems |pdfUrl=https://ceur-ws.org/Vol-2215/paper_16.pdf |volume=Vol-2215 |authors=Michele Ruta,Floriano Scioscia,Giuseppe Loseto,Filippo Gramegna,Agnese Pinto,Eugenio Di Sciascio |dblpUrl=https://dblp.org/rec/conf/woa/RutaSLGPS18 }} ==Semantic-based Social Intelligence through Multi-Agent Systems== https://ceur-ws.org/Vol-2215/paper_16.pdf
            Semantic-based Social Intelligence through
                      Multi-Agent Systems
    Michele Ruta, Floriano Scioscia, Giuseppe Loseto, Filippo Gramegna, Agnese Pinto, Eugenio Di Sciascio
                            Polytechnic University of Bari - via E. Orabona 4, Bari (I-70125), Italy
        {michele.ruta, floriano.scioscia, giuseppe.loseto, filippo.gramegna, agnese.pinto, eugenio.disciascio}@poliba.it


   Abstract—Current technologies and market solutions are far              and technical use cases are quite far from such levels of
from fulfilling the Ambient Intelligence (AmI) vision of simplified        intelligence, automation and adaptivity. A limited flexibility is
people-environment interactions. Even though Despite recent                possible, as devices are logically associated at the application
solutions based on Internet of Things (IoT) technologies provide
the needed infrastructure, most approaches suffer from inade-              level by means of static profiles, defined during systems
quate levels of intelligence and autonomy. This paper proposes             deployment. This is also the case of domotics –i.e., Home and
a novel semantic-based Multi-Agent System (MAS) framework                  Building Automation (HBA)–, one of the widespread examples
complying with the emerging Social Internet of Things paradigm             of AmI for environmental control. In most established HBA
devoted to improve both automation and adaptivity: device agents           standards, solutions are centralized and proprietary: changing
self-organize in social relationships, interacting autonomously
and sharing information, cooperating and orchestrating ambient             possible configurations or introducing new devices typically
resources. A service-oriented architecture allows collaborative            require the intervention of qualified practitioners. Even recent
dissemination, discovery and composition of service/resource               “smart home” platforms introduced by IT companies still
descriptions. Decision and choreography capabilities of software           depend heavily on manual configuration and provide only
agents leverage Semantic Web languages at the knowledge                    rudimentary levels of automation [3].
representation layer and a mobile-oriented implementation of
non-standard inferences for semantic matchmaking. Benefits of
the proposal are highlighted through an AmI case study in the                 This paper presents a novel MAS paradigm at the con-
field of Home and Building Automation (HBA). A comparison                  vergence of the Semantic Web of Things (SWoT) [4] and
with the state of the art is also provided.                                Social Internet of Things (SIoT) [5] visions. IoT devices act
   Index Terms—Semantic Web of Things, Social Agents, Ambient              as socially intelligent agents, capable of autonomous config-
Intelligence, Service Discovery
                                                                           uration, coordination and orchestration. Interaction patterns
                                                                           inspired by SNSs allow agents to establish relationships,
                       I. I NTRODUCTION
                                                                           share information, exchange requests and services, in a dy-
   The advent of Social Networking Services (SNSs) has had a               namic, decentralized and collaborative fashion. Agents ex-
deep impact on how people communicate and interact. Starting               ploit Knowledge Representation (KR) technologies borrowed
from personal user profiles containing general information,                from the Semantic Web to express and circulate knowledge
typical elements of SNSs include: the capability to engage                 about themselves and the context they are dipped in. In
asymmetrical (e.g., follower/followee) or symmetrical (e.g.,               addition, the semantic-based matchmaking implemented in a
friendship, group) relationships among users; a personal log               resource-efficient mobile engine [6], on a moderately expres-
(wall) to post text and/or multimedia items; the possibility to            sive fragment of the Web Ontology Language (OWL2) [7],
mark (tag) contacts to draw their attention to a given item,               supports the social intelligence through discovery, aggregation
as well as to append comments and reactions (e.g., like) to                and ranking of available social entities. As agents acquire
elements published by other users. These basic primitives can              new knowledge about their context, both their configurations
be combined to support several interaction models, granting                and the environmental services evolve: the MAS becomes a
users high flexibility in the way they share information,                  social network, where individual device interactions produce
communicate, collaborate and search for resources of interest.             emergent behaviors toward high-level goals, without requiring
   Endowing autonomous agents with social capabilities can                 explicit user commands. The paper reports on a case study
transfer benefits of SNSs to Multi-Agent Systems (MASs),                   in the field of HBA: current approaches are compared with
particularly to complex, dynamic and loosely coupled ones.                 the one proposed here in order to assess possible benefits and
This is the case of Internet of Things (IoT) contexts for Am-              evidence the added value of the proposal.
bient Intelligence (AmI) [1], where networks of lightweight
agents on highly heterogeneous mobile and embedded devices                    The remainder of the paper is organized as reported in what
provide context-aware, adaptable, unobtrusive and intelligent              follows: after related work discussion in Section II, Section
support to users’ activities [2]. In AmI, the environment should           III describes the proposed approach. An AmI case study is
adapt to changes in external conditions as well as users’                  presented in Section IV to clarify the proposal, including a
personal preferences and requirements, even anticipating needs             comparison with state-of-the-art technologies for IoT-oriented
and behaviors. Current solutions available for commercial                  HBA. Conclusion in Section V closes the paper.




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                     II. R ELATED WORK                                                               TABLE I
                                                                                      N ETWORK ENTITIES AND SOCIAL FEATURES
   The study in [8] observed that the majority of SNS users
                                                                              Technical feature               Social environment
access them regularly, as they find both enjoyment and use-                   Object / Device / Application   Social agent
fulness. Higher numbers of connected users –and in particular                 Functional profile              Service
complementary ones [8]– increase opportunities for finding                    Object pairing                  Social relationship
needed information and services. These benefits can also apply                                                (friend/follower)
                                                                              Object communication            Social interaction
to social networks of objects, which work as independent                      Object configuration            Distributed service discovery
agents and interact for information and resource/service shar-                update/adaptation
ing.                                                                          Object log                      Wall
                                                                              Object command                  Post
   One of the earliest examples of social object capabilities can             Object reply                    Comment
be found in [9], a proposal aimed at distributed OWL Knowl-                   Functionality                   Tag & Like
edge Base management and reasoning. Upon connection to the                    activation/deactivation
network, embedded devices proactively exchanged information
in a handshake. “Requester” devices, endowed with reasoning
                                                                         only manual configuration, but also changes to the reference
capabilities, allowed users to execute queries, which were
                                                                         ontology. Also the proposals in [20], [21] relied on rule-
automatically distributed among requester’s “known” devices.
                                                                         based reasoning, where the system state should fully match
Unfortunately, reasoning capabilities were curbed by the re-
                                                                         rule conditions in order to trigger a rule. Unless only ele-
strictions of the adopted query language, limiting the practical
                                                                         mentary rules are adopted, however, full matches are quite
interest of supported use cases.
                                                                         rare in realistic scenarios, where entities are described by
   The approach proposed in this paper is conceptually close
                                                                         heterogeneous and often contradictory annotations. Finally, in
to [5], where SIoT has been envisioned as a social evolution
                                                                         [22] a semantic Service-Oriented Architecture (SOA) enabled
of the Internet of Things, with agentified objects capable of
                                                                         discovery and composition of semantic services. For greater
setting mutual relationships and exploiting them to exchange
                                                                         autonomy and flexibility, in this paper the SOA paradigm
information and services, without requiring interactions with
                                                                         has been coupled with a MAS of socially intelligent agents.
users or human-oriented SNSs. Conversely, earlier efforts such
                                                                         The proposal extends the early conceptual and architectural
as [10] aimed to make objects aware of people’s social context.
                                                                         elements introduced in [23].
Networks of socially intelligent objects were analyzed in [11],
by defining key metrics about nodes and links, adapted from                        III. A NETWORK OF SEMANTIC AGENTS
the literature on SNSs analysis. An ontology formalized the                 The proposed approach aims at agent coordination in pur-
definitions, and social objects could use them to manage their           posely infrastructured environments and particularly in do-
policies, friends and reputation. A further step toward social           motics scenarios through interaction paradigms inspired by
agency is object blogging [12], i.e., an object’s ability to             social networks. Devices are fully enabled in sharing re-
self-describe autonomously on the Web or in a local area                 sources/services, making decisions, disseminating requests and
network to support intelligent interactions. This was previously         gaining responses through a distributed peer-to-peer protocol.
explored in RFID contexts [13] and constitutes an evolution of           Shared knowledge fragments about devices themselves, func-
proposals requiring human intervention [14], [15]. The work              tional profiles and context are advertised via a decentralized
in [16] identified smartphones as means to put people back in            service-oriented architecture. The social relationship and the
the loop of ubiquitous autonomous social MASs. Smartphones               discovery models outlined hereafter integrate in a unified
are ideal tools for learning about their owners and context, in          social agent space both single-purpose physical objects and
order to work as their digital counterparts, exposing dynamic            applications deployed on multi-purpose devices.
personalized profiles in the social agent choreography. Sev-
eral works have already explored smartphones and wearable                A. Framework and architecture for social agents
devices to model users’ activities, preferences and contexts                Table I highlights basic correspondences of entities and
[17].                                                                    features in a generic AmI domain to the proposed social MAS
   Semantic-based approaches are not uncommon in AmI                     environment. This applies particularly to domotics and HBA.
and particularly in domotics. Building automation ontologies             Every object acts as a social agent: it exposes an individual
were used for system design and commissioning, device                    profile describing its general features (e.g., device type, lo-
description, data modeling and access, ambient control [18].             cation, hardware details) as well as the resources/services it
The ontology-based system in [19] delivered context-aware                can provide through possible configurations. An agent is able
customized information to different kinds of users. Queries              to become friend and/or follower of other agents. According
matched device and user descriptions in OWL while rules                  to the different kinds of interactions described hereafter, it
implemented temporal and extra-logical constraints, achiev-              can write posts on either its wall or friends’ walls when its
ing overall capabilities similar to Complex Event Processing             settings or capabilities change, and also when it produces new
(CEP) architectures. Nevertheless, integration appears as a              or updated information after a context analysis. Each post
serious limitation, because installing new devices required not          contains perceptions and events observed by the social agent.




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In the proposed SOA-based MAS, it is considered as a request               The proposed MAS complies with a range of different
for system reconfiguration through distributed semantic service          scenarios and contexts, because it is inherently platform-
discovery, which can be exploited by:                                    independent and general-purpose. All social features reported
                                                                         in Table I can be modeled regardless of the particular
  • sensor agents, such as a weather station, which can
                                                                         application-layer communication protocol. Anyway, a first
    observe the environment and share data but don’t have
                                                                         implementation has been proposed in [24] based on the
    actuation capabilities;
                                                                         Constrained Application Protocol (CoAP) [25], a lightweight
  • actuator agents, such as a lamp or a fan, which can react
                                                                         Web of Things protocol for machine-to-machine interaction.
    to environmental changes but have limited or no sensing
    facilities: by reading posts, they become aware of current
    conditions and activate/deactivate some services;                    B. Semantic-based social network interaction
  • smart agents, endowed with both sensors and actuators: if
                                                                            In the proposed framework, social agents are distinguished
    a smart agent does not have all the capabilities needed to           in two possible families: full ones, able to execute the inference
    comply with the perceived changes, a discovery process               tasks described above, and basic ones, endowed with low
    is started to find peers providing further suitable services,        memory and low (or no) computing capabilities, which can
    as described in Section IV-A.                                        only provide sensing/acting services, but cannot perform au-
   Semantic annotations referred to ontologies in OWL2 [7]               tonomous reasoning. A pair of agents can engage in two kinds
are used to express agent profiles, service descriptions and             of social relationships. Through the bidirectional friendship
requests. Being formally grounded on Description Logics                  link, they can exchange both information and services. In
(DLs) semantics, they are both machine understandable and                particular, they became able to: (i) read and write on each
human readable. In particular, this paper refers to the OWL2             other’s wall; (ii) request the friend’s service descriptions; (iii)
fragment corresponding to the ALN (Attributive Language                  activate or deactivate the friend’s services. When becoming
with unqualified Number restrictions) DL, which supports                 friend with a full agent, a basic agent can select it as semantic
standard and non-standard inferences with polynomial com-                facilitator, i.e., reasoning helper. Conversely, an agent can
plexity [6].                                                             follow another one if interested only in receiving updates
   Decision capabilities of social agents are enacted through            published on its wall, i.e., becoming an observer through a
a collaborative service/resource discovery. This process lever-          unidirectional relationship.
ages semantic matchmaking, i.e., the task aimed at retriev-                 Following/friendship criteria are automatically verified by
ing and ranking the most relevant resources for a given                  means of a matchmaking process involving the device profiles.
request, where both requests and resources are satisfiable               Two agents are good candidates for friendship if one or more
concept expressions w.r.t. a common ontology T . Classic                 of the following conditions are met: (i) strong co-location,
subsumption/satisfiability approach is extended here by means            i.e., devices are placed in the same room/area; (ii) parental
of the Concept Abduction, Concept Contraction and Concept                or co-ownership, i.e., they are from the same manufacturer
Covering [6] non-standard inference tasks in ALN :                       or belong to the same owner; (iii) co-working, i.e., they are
- Concept Contraction: if annotations of a request R and a               able to cooperate closely as they share annotations referred
given resource S are not compatible (i.e., an explicit clash             to the same ontology and provide functionalities related to the
arises from their logical conjunction), Contraction determines           same activity (e.g., room lighting) or observed parameter (e.g.,
what part G (for Give up) of the request is conflicting with             indoor temperature). On the other hand, a follower request is
S. If one retracts G from R, a concept K (for Keep) remains,             more appropriate in case of: (i) weak or sporadic co-location,
which is a contracted version of R compatible with S. G                  such that information produced by an agent can still be useful
explains “why R and S are not compatible”;                               to other ones to characterize their own context, but at the same
- Concept Abduction: if R and S are compatible, but S does               time they need/prefer to start independent discovery requests;
not satisfy R completely, Abduction determines what should               (ii) no co-ownership; (iii) weak co-working relationship, i.e.,
be hypothesized in S in order to obtain a full match. The                direct interactions would have low usefulness, because e.g., the
solution H (for Hypothesis) to Abduction explains “what is               two agent profiles are incompatible w.r.t. a common reference
requested in R and not specified in S”. By computing penalty             ontology, i.e., they are significantly different (note that even
metrics linked to G and H [6], Contraction and Abduction                 a follower relationship is inappropriate in case of profiles
further enable a logic-based relevance scoring of a set of               referring to separate ontologies, as that implies agents belong
resources w.r.t. a certain request;                                      to totally different domains, e.g., HBA and healthcare).
- Concept Covering: in AmI scenarios such as domotics, it is                For a broader range of interaction patterns, the framework
often useful to compose multiple services/resources in order             also permits being both a friend and a follower of the same
to satisfy a complex request. Given a request R and a set                agent: this is useful in highly heterogeneous scenarios. In
of resource instances S = {S1 , S2 , ... , Sn }, Covering finds          any case, a friendship/follow request can be rejected if the
out a pair hSc , Hi, where Sc ⊆ S contains resources whose               above conditions are not verified or the maximum number
aggregation satisfies R as much as possible, while H is the              of friends/followers has been reached w.r.t. processing and
(possible) remaining part of R not covered by concepts in Sc .           memory limits of the invited agent. In practice, however, by




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enlarging its social network an agent increases opportunities
                                                                              A1                         A2                        A3
for useful cooperation, hence rejections should be infrequent.
   Like in human-oriented SNSs, agents’ walls are the main                         writeInWall(P1)                                  1) write a post
knowledge sharing medium. The proposed framework supports                          covering(R1)
                                                                                   updatePost(P1)                                   2) local discovery
both push and pull models, exploiting the above relationships:
                                                                                     postInWall(P2)           writeInWall(P2)       3) collaborative
  • push: if agent Ai wants to receive updates from peer                                 ACK
    Aj automatically, it will ask to become a follower. If                                                    covering(U1)             discovery
                                                                                                              updatePost(P2)
    accepted, follower Ai will be able to start a distributed                                                   postInWall(P3)
    discovery session when it receives a notification of a new                                                                          processing like A2
                                                                                                                    ACK
    post or comment on the wall of the followed agent Aj ;                               notify()                                   4) receive
  • pull: if Ai wants to access Aj ’s wall on demand, it                             readComment(P2)                                   notifications
    will ask to become a friend. By doing so, Ai will also                              comment
                                                                                    updatePost(P1)
    automatically grant Aj access to its own wall. Then Ai
    will perform semantic matchmaking if Aj writes a post
    on Ai ’s wall, during a collaborative covering as reported                     Fig. 1. Sequence diagram for a distributed reconfiguration
    in Figure 1.
Each agent will choose a model –or even both– based on its                                                            Friend
goals and strategies. These elements are relevant and conform
to the general behavior policy of the MAS, anyway they are
outside the scope of the paper.                                                            AC
   When an agent detects an event (e.g., a change in internal or
environmental parameters) and conditions require adaptation –                                                              AS
i.e., modification to the functional configuration of itself and/or
of nearby devices– it will write a post on its wall. As these
trigger mechanisms are fundamentally domain-dependent and
application-oriented, the framework does not prescribe specific
solutions. In any case, the written post P will consist of a
pair hR, Li, where R is the request issued by the node –                             L
expressed as a semantic annotation w.r.t. a reference ontology–                                                                         SC
and L is the like value. The like reaction to a post has been
mutuated from human-oriented SNSs, but in the proposed
approach it is a real value in [0, 1] instead of a Boolean                                           Fig. 2. Case study scenario
value. It represents the coverage ratio of request R, as resulting
from Concept Covering in the collaborative service discovery
process. Specifically, if U is the uncovered part returned by              steps 2) - 3).
the Concept Covering of R with a set of available services,                4) When Ai receives the notification of Pj , it reads the
the associated like value is computed as L = 1 − norm(U           )        comment from the friend’s wall and appends it to Pi in order
                                                          norm(R)
using the norm on concept expressions described in [6]. An                 to update the status of the request. Finally, Ai updates the like
example of the whole process is in Figure 1, composed of the               value accordingly.
                                                                              The choice of friend(s) to call in the above step 3 basically
following steps:
                                                                           depends on heuristic preference criteria, such as the number
1) When an agent Ai detects a reconfiguration is needed, it
                                                                           and type of services exposed by the friend (known at friendship
writes a post Pi on its own wall. Li is initialized to 0.
                                                                           establishment time), network latency or friend’s computational
2) If Ai is a basic device, go to step 3. Otherwise, Ai executes
                                                                           resources.
the Concept Covering task on the local set of service anno-
tations S (Section III-A). Ai activates the selected services                   IV. C ASE STUDY: FROM OBJECTS TO AGENTS FOR
and adds a comment Ci to Pi as a pair hUi , Ti i, where Ui                                   A MBIENT I NTELLIGENCE
is the uncovered part of Ri and Ti tags the selected local                   The case study presented here would clarify the social
services/resources. Moreover, the value of Li is updated as                and collaborative potentialities of the proposed MAS frame-
per the above formula.                                                     work. To this aim, a specific scenario is targeted: the self-
3) If Ri is not completely covered, Ai selects a friend Aj and             orchestration capability of agentified home devices allows to
writes a post Pj =hRj , Lj i) on its wall. Particularly, if Ai has         evidence the AmI capabilities of the above approach.
executed step 2, Rj is set to the uncovered part Ui , otherwise
Rj is equal to Ri and Lj is 0. Writing Pj on the friend’s                  A. Illustrative example
wall automatically implies that Ai must be notified when a                    Figure 2 depicts the reference testbed recalling the case
comment is added to the post. Aj recursively executes the                  study; a house contains a social network of semantic-enabled




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AS_Request: (detectsOutdoorLuminosityCondition some)               Lamp_On: (detectsOutdoorLuminosityCondition some)
and (detectsOutdoorLuminosityCondition only                        and (detectsOutdoorLuminosityCondition only
LowLuminosityCondition) and (detectsIntrusionEvent                 LowLuminosityCondition) and (detectsIntrusionEvent
some) and (detectsIntrusionEvent only                              some) and (detectsIntrusionEvent only
IntrusionEvent) and (detectsOccupancyCondition some)               IntrusionEventForLamp)
and (detectsOccupancyCondition only (not
OccupantPresence))                                                 Lamp_M edium: (detectsOutdoorLuminosityCondition
                                                                   some) and (detectsOutdoorLuminosityCondition only
           Fig. 3. Request posted by the alarm system AS           MediumLuminosityCondition) and
                                                                   (detectsOccupancyCondition some) and
                                                                   (detectsOccupancyCondition only OccupantPresence)
F ull_Close: (detectsPrecipitationCondition some) and
(detectsPrecipitationCondition only Rain) and                      Lamp_Of f : (detectsOutdoorLuminosityCondition some)
(detectsWindCondition some) and                                    and (detectsOutdoorLuminosityCondition only
(detectsWindCondition only StrongWind) and                         HighLuminosityCondition) and
(detectsIntrusionEvent some) and                                   (detectsOccupancyCondition some) and
(detectsIntrusionEvent only                                        (detectsOccupancyCondition only (not
IntrusionEventForShutter) and                                      OccupantPresence))
(detectsOccupancyCondition some) and
(detectsOccupancyCondition (not OccupantPresence))                               Fig. 5. Dimmer lamp L service annotations
Half _Close: (detectsPrecipitationCondition some) and
(detectsPrecipitationCondition only (not Rain)) and
(detectsWindCondition some) and                                    listed in Figure 4, Concept Covering selects only
(detectsWindCondition only ModerateWind)                           the Full Close service, provided by SC: this is
Open: (detectsPrecipitationCondition some) and                     basically due to commonality with the request
(detectsPrecipitationCondition only (not Rain)) and                of       concepts         (detectsOccupancyCondition
(detectsWindCondition some) and                                    some)          and        (detectsOccupancyCondition
(detectsWindCondition only LightBreeze) and
(detectsOutdoorLuminosityCondition some) and                       (notOccupantPresence))                  (service     descriptions
(detectsOutdoorLuminosityCondition only                            provided by the air conditioner are not reported because it
HighLuminosityCondition)                                           does not offer any useful feature). AS comments its post
           Fig. 4. Shutter controller SC service annotations       including both a tag to the Full Close shutter service and
                                                                   the uncovered part of the request. In order to further cover
                                                                   the post, AS can select one of its friends and forward
agents embedded in the following devices: an alarm system          the uncovered part. Since SC has provided the highest
(AS), a rolling shutter controller (SC), an air conditioner (AC)   contribution in the first covering step, AS posts on SC’s
and a dimmer lamp (L). The blue arrows in Figure 2 specify         wall the OWL2 annotation of the uncovered part, reported in
the existing friendship relations between the above agents.        Figure 6. When SC receives the message, it recursively starts
   According to the criteria suggested in Section III-B, the       a covering process, which involves the services exposed by
agents set friendship relations because they are in the same       its friend L (Figure 5). The Covering inference task selects
location and share functionalities useful to improve comfort       the Lamp On service, which completely covers the remaining
or security in the house. Not all agent pairs are friends: in      part of the initial request. SC therefore comments the post on
particular, Figure 2 shows L befriends SC only. Besides, each      its wall by tagging the activated service and updating the like
agent has embedded sensing and/or actuating capabilities and       value to 1. Further agents do not need to be involved, as the
exposes a set of functional profiles to its friends.               request is fully satisfied. Finally, AS receives a notification of
   Let us suppose it is evening and AS detects an intrusion        the comment to its post on SC’s wall, it reads the comment
while there is nobody in the house. AS writes a new post           and sees the initial request has been completely fulfilled. As
on its wall, representing what it has sensed as an OWL2            a consequence, it updates the like value of the post on its
annotation. Figure 3 shows a formalization of the post in          wall and the discovery process stops. The house has changed
OWL2 Manchester syntax [26]. Service requests and descrip-         its configuration by closing shutters and switching the lamp
tions are expressed w.r.t. the reference ontology (not reported    on reacting to the intrusion alert.
due to space constraints), by specifying the context conditions
suitable for the activation of a given service. Then AS starts     AS_Req_U ncovered: (detectsOutdoorLuminosityCondition
                                                                   some) and (detectsOutdoorLuminosityCondition only
a Concept Covering process using the content of the post as        LowLuminosityCondition) and (detectsIntrusionEvent
request, while services are taken from AS’s cache of available     some) and (detectsIntrusionEvent only
functionalities exposed by all its direct friends, i.e., SC and    IntrusionEventForLamp)
AC. Freshness of cache entries is checked via preliminary               Fig. 6. OWL2 annotation of the uncovered part of AS Request
conditional requests: a service annotation will be retrieved
again only if it has been updated, otherwise AS can directly         It is useful to point out that the Intrusion class was
use the cached copy. This procedure guarantees the covering        defined as more specific than both IntrusionForLamp and
task is performed using the latest descriptions of all available   IntrusionForShutter, i.e., it should require services
services.                                                          both from a lamp and a shutter controller. Such a model-
   According to the semantic service descriptions                  ing pattern allows activating functionalities (Full Close and




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                                                                    TABLE II
                                           C OMPARISON WITH CURRENT I OT- ORIENTED FRAMEWORKS FOR HBA

 Features                  KNX IoT                  IzoT Platform              Dog Gateway            Eclipse SmartHome         Proposed Approach
 Home Area Network                                                             multi-protocol         multi-protocol            multi-protocol
                           EIB/KNX                  LonTalk
 reference protocol                                                            over HTTP              over HTTP                 over CoAP
 Network architecture      centralized              centralized                centralized            centralized               full P2P
                                                    via LonBuilder                                    Domain-Specific
 Network/devices                                                               XML configuration                                autonomous social
                           via ETS software         software or XML                                   Language (DSL)
 configuration                                                                 files                                            agents configuration
                                                    configuration files                               configuration files
                           edit network/devices     edit network/devices       edit network/devices   edit network/devices      agents
 Add/remove devices
                           configuration            configuration              configuration          configuration             self-configuration
 Multi-protocol                                                                                       node acting               smart agents acting
                           KNX gateway              IzoT gateway               Dog gateway
 communication                                                                                        as gateway                as gateways
                           static, defined during   static, defined during     dynamic, based on      static, defined during    dynamic, based on
 Device binding
                           network configuration    network configuration      device profile         device configuration      friendship relationships
 Scenarios                 static, defined during   static, defined during     dynamic, exploiting    static, based on an ECA   dynamic, exploiting
 configuration             network configuration    network configuration      rule-based reasoning   rule engine               non-standard inferences
                                                                                                                                yes, through
 Service composition       no                       no                         no                     no
                                                                                                                                distributed covering
                           proprietary              proprietary, XML-based
 Message data format                                                           OWL 2                  XML                       OWL 2
                           (KNX specs.)             (LonTalk specs.)
 Standardized              KNX IoT                                             WebSocket and                                    CoAP
                                                    HTTP RESTful API                                  HTTP RESTful API
 framework interface       Web Services                                        HTTP RESTful API                                 RESTful interface



Lamp On) of different devices that are fired when the same                     here fully complies with resource-constrained scenarios (by
event is detected.                                                             supporting a P2P architecture and lightweight protocols such
   The above example has been kept simple for the sake of                      as CoAP). Another distinguishing feature is a certain expres-
clarity, with relatively short service annotations and purely re-              siveness in the possibility of device description and modeling
active MAS behavior. Notwithstanding, the adopted inferences                   (by adopting semantically rich formalisms as OWL 2). Finally,
allow managing more articulated specifications with detailed                   noteworthy is the support for an articulated discovery through
constraints. Moreover, the proposed approach fully supports                    both exact and approximated matches formally grounded on
proactive agents, which can fire periodic or sporadic internal                 service/resource composition.
events to trigger collaborative service discovery and MAS                         Quantitative performance results of the proposed approach
configuration updates. Finally, the small MAS described in                     are not provided here, but the semantic service discovery and
the example can be federated with other MASs in nearby                         orchestration based on Concept Covering is arguably the most
zones (e.g., of adjacent houses) by means of social interaction                computationally demanding task, while social relationship
capabilities, ensuing from the possibility to establish friendship             management is not resource-intensive. Results obtained in
or follower relationships between agents across zones. This                    [23] for an earlier version of this framework allow optimistic
allows taking advantage of sensing/acting capabilities of a                    expectations about feasibility on IoT device networks and
larger agent pool, as well as compensating possible deficits                   compatibility with performance requirements of HBA and AmI
of individual agents and zones reaching a concrete ambient                     scenarios.
intelligence in real-life significant scenarios.                                                     V. C ONCLUSION
B. Evaluation                                                                     The paper proposed a novel semantic-based social MAS
                                                                               framework. Though presented in a HBA scenario, features
   In order to assess both peculiarities and capabilities of                   and approach are general-purpose and target several possible
the proposed semantic-based social MAS, a systematic com-                      Ambient Intelligence records. The application domains are
parison with existing IoT-oriented AmI approaches has been                     basically inherited from ontologies modeling the reference
carried out. Particularly, HBA platforms have been selected                    implementation.
as reference systems. In more detail, the following solutions                     The proposed approach enables autonomic agent interaction
have been considered: KNX IoT1 ; IzoT Platform2 , originally                   and a semantic-enhanced service/resource discovery grounded
developed by Echelon Corporation for the Industrial IoT but                    on the formal annotation of devices, environment and phe-
also exploited for HBA applications; Dog Gateway3 [20];                        nomena. A case study and a comparison with state- of-the-art
Eclipse SmartHome4 .                                                           techniques help highlighting peculiarities of the proposal.
   Table II highlights most relevant elements: it emerges that,                   Future work will include further investigation and extension
to the best of our knowledge, only the approach proposed                       of the social presence capabilities of agents, as well as novel
  1 http://www.knx.org/knx-en/Landing-Pages/KNX-IoT
                                                                               interaction patterns. A full prototypical implementation is
  2 http://www.echelon.com/izot-platform                                       expected to evidence possible optimization directions and scal-
  3 http://dog-gateway.github.io/                                              ability concerns. Finally, graphical visualizations of devices’
  4 http://www.eclipse.org/smarthome/index.html                                walls are being implemented.




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