1. Michel Nitti, Roberto Girau, Alessandro Floris, Luigi Atzori
On adding the social dimension to the Internet of Vehicles: friendship and middleware
Michel Nitti, Roberto Girau, Alessandro Floris, Luigi Atzori
Department of Electrical and Electronic Engineering – University of Cagliari
도윤형

2. abstract
In this paper, we analyze the combination of Vehicular Ad-hoc NETworks (VANETs) with the Social Internet of Things (SIoT), i.e., the Social Internet of Vehicles (SIoV).
In the SIoV every vehicle is capable of establishing social relationships with other vehicles in an autonomous way with the intent of creating an overlay social network that can be exploited for information search and dissemination in VANET applications.

3. abstract The contribution of this paper is two-fold:
firstly, we define some relationships which can be established between the vehicles and between the vehicles and the road side units (RSUs)
secondly, we propose a SIoV middleware which extends the functionalities of the Intelligent Transportation Systems Station Architecture (ITS SA)

4. Introduction-VANET
Vehicular Ad-hoc NETworks (VANETs) are particular Mobile Ad-hoc NETworks (MANETs) in which nodes can be mobile or static.
Mobile nodes are vehicles while static nodes are road-side units (RSUs).

5. Introduction-VANET
In VANETs, the vehicles are equipped with an On-Board Unit (OBU) through which they can communicate with other vehicles (Vehicle-to- Vehicle or V2V communication) and with RSUs (Vehicle-to- Infrastructure or V2I communication) by employing wireless short- range protocols as IEEE p.
Furthermore, the vehicles and/or the RSUs can be able to connect to the Internet by using mobile cellular systems.

6. Introduction-IoT and IoV
The integration of the concept of the Internet of Things (IoT) with the VANETs has brought to a novel paradigm, namely the Internet of Vehicles (IoV); by allowing the vehicles to be durably connected to the Internet, they can form the IoV that is an interconnected set of vehicles which provide information for common services such as traffic management and road safety.
the integration of social networking concepts into the IoV brings to the Social Internet of Vehicles (SIoV) paradigm, as an extension of the Social Internet of Things (SIoT) concept.

7. Introduction-SIoT
The SIoT is a social network where every node is an object capable of establishing social relationships with other things in an autonomous way while taking into account the constraints set by the owner.
The possibility to establish social relationships among objects has the potentials to solve problems of network navigability and information/service discovery when the IoT is made of huge numbers of heterogeneous nodes.

8. Introduction-proposal
In this paper, starting from the SIoT concepts, we define some relationships which can be established between the vehicles taking part to the SIoV.
These relationships can be either static, as the [Parental Object Relationship] established between vehicles belonging to the same automaker, or dynamic, as the [Social Object Relationship] established between vehicles that come into contact through V2V communications.
By establishing relationships among each other, the vehicles form a network of friendships.

9. Introduction-proposal
we propose an initial definition of the SIoV middleware by extending the functionalities of the [Intelligent Transportation Systems Station Architecture] (ITS SA).
Furthermore, additional modules for the Security and Management panes have been defined.

10. Background-VANET and IoV
Most state-of-the-art works considered VANETs for different applications which can be mainly classified as active road safety applications, traffic efficiency and management and infotainment applications.
Since VANETs are based on V2V and V2I communications, which employ wireless short-range protocols, information dissemination is essential to efficiently transmit the messages among the vehicles.

11. Background-VANET and IoV
Most VANET routing protocols proposed in the literature are focused on disseminating information by exclusively exploiting wireless short-range communications.

12. Background-VANET and IoV
we are interested in the design of a IoV, which needs vehicles to be durably connected to the Internet, we focus on state-of-the-art works which considered mobile cellular systems in VANETs in addition to V2V/V2I wireless short range protocols.
Assume: vehicles are equipped with both 3G radio and short range radio for V2V and V2I communications, so that each vehicle can directly deliver a packet via 3G or via multi-hop transmissions.

13. Background-VANET and IoV
The IoV paradigm brings to many unprecedented challenges, such as how to find the right vehicle that can provide the right service and to which extent trust the information provided by other vehicles/RSUs.
For this reason, in this paper, we assume that each vehicle is connected to the Internet and then it is equipped with an OBU with both 3G radio for Internet connection and short-range radio for V2V and V2I communications.

14. Background-SIoT
The SIoT is intended as a social network where every node is an object capable of establishing social relationships with other things in an autonomous way with respect to the rules set by the owner.
The authors defined various types of social relationships in which things can be engaged, such as parental object relationship, co- location object relationship, co-work object relationship, ownership object relationship and social object relationship.

15. Background-SIoT
The parental object relationship is defined among similar objects built in the same period by the same manufacturer; this relationship will not change over time.
Co-location and co-work object relationships are determined whenever objects constantly reside in the same place or periodically cooperate to provide a common IoT application.
Changes are frequent for these relationships and are usually based on time duration of co-location/co-working and on the frequency of the interaction.

16. Background-SIoT
The ownership object relationship is defined for objects owned by the same user.
the social object relationship is established when objects come into contact, sporadically or continuously, for reasons purely related to relations among their owners.

17. Background-SIoT
The objects, if properly authorized, autonomously exchanges their social profile.
The driving idea is that devices with similar characteristics and profile can share best practice to solve problems already faced by friends.
Besides social relationships, the authors proposed a three-layer SIoT architecture for both the client and server sides.

18. Background-SIoT
The main innovations, with respect to the others IoT platforms, are the possibility for the objects to create their own relationships, based on the rules set by their owners, and to create groups of interest as it happens in human social networks.

19. The Social Internet of Vehicles -SIoV relationship
The IoV represents a homogenous set of objects with high mobility where each vehicle is a source of key information for different types of applications, such as active road safety or traffic management efficiency.
In this scenario, a very large amount of data is streamed from vehicles and RSUs so that the discovery of the object that can provide the desired service can result quite difficult.

20. The Social Internet of Vehicles -SIoV relationship
Fig. 1. Relationships created in the Social Internet of Vehicles scenario.
Green lines represent Parental Object Relationships, blue line represent Social
Object Relationships and yellow lines represent Co-Work Object Relationships

21. The Social Internet of Vehicles -SIoV relationship
vehicles belonging to the same automaker and originated in the same period establish a Parental Object Relationship (POR):
these relationships can give useful information about the status of a vehicle and can be exploited when providing diagnostic services and remote maintenance to the users.

22. The Social Internet of Vehicles -SIoV relationship
vehicles that come into contact through V2V communications create a Social Object Relationship (SOR). Vehicles meet randomly, e.g., when their owners go to work and then share the same way:
more often two vehicles meet, the stronger the relationship that links each other and the higher the value it provides in service discovery and trustworthiness evaluation.

23. The Social Internet of Vehicles -SIoV relationship
The benefits given from the establishment of SORs are very important in SIoV scenario:
most of the contents provided by the vehicles are related to certain areas and to limited times.

24. The Social Internet of Vehicles -SIoV relationship
Example: the communication of road incidents to vehicles proceeding toward the crashed areas or the sharing of useful information about traffic conditions or petrol stations.
SORs take into account common vehicles paths and locations which permit to create social networks among vehicles strictly related to determined areas.

25. The Social Internet of Vehicles -SIoV relationship
in a similar way, when vehicles meet continuously with RSUs through V2I communications, they create a Co-Work Object Relationship (CWOR) with them.
These relationships can be useful to provide traffic information or to guide the drivers in less congestionated routes.

26. The Social Internet of Vehicles -SIoV relationship
The combination of these relationships brings to the creation of the social network of vehicles where information can be gathered in a distributed manner by crawling the network from friend to friend in the same way humans do in their social networks.
Moreover, the SIoV evolves according to the activities of vehicles and RSUs so that it can quickly adapt to the mobility scenario, by creating new links or adapting the strength of the existing ones.

27. The Social Internet of Vehicles -SIoV relationship
Applications
Relationships
Description
Diagnostic service
POR
Vehicles contact friends in order to know if they have had/solved a similar issue.
Traffic information
SOR
Vehicles obtain from friends, that usually travel in the same
routes, updated information about traffic condition
Community services
CWOR
RSUs communicate with vehicles to provide information
about road conditions or maintenance
Table 1. SIoV Sample Applications

28. The Social Internet of Vehicles -SIoV middleware
VANETs can be viewed as a component of the Intelligent Transportation Systems (ITS), i.e., vehicular network applications that aim to provide innovative services related to different modes of transport and traffic management.
Fig. 2. ITS Station Architecture(SA) defined in ISO and ETSI EN

29. The Social Internet of Vehicles -SIoV middleware
Fig. 3. Integration of the SIoT middleware in the ITS Station Architecture

30. The Social Internet of Vehicles -SIoV middleware
Management: The Management pane contains three major features.
relationship management module
feed sync module
logic controller module

31. The Social Internet of Vehicles -SIoV middleware
The relationship management is a key module in the middleware.
it has the task to retrieve from the server information about the relationships created on the basis of the owners control settings, since the vehicles have not the intelligence to select the friendship.

32. The Social Internet of Vehicles -SIoV middleware
The feed sync module handles the transmission and reception of the feed.
During transmission, it takes all the data from the different applications, aggregates them whenever possible, and send to the server through the SIoV APIs.
during reception, it performs a parsing on the received data and routes them to the module or applications for which they are intended.

33. The Social Internet of Vehicles -SIoV middleware
The logic controller module is the core of the middleware, since it handles all the different events, such as the timing to send the data or the reading by the sensors:
these events can be driven by the applications or by the middleware itself.

34. The Social Internet of Vehicles -SIoV middleware
Security: In the Security pane the trustworthiness management module is added.
this module aims at understanding how the information provided by the other vehicles or RSUs shall be processed.

35. The Social Internet of Vehicles -SIoV middleware
Facilities: The Facilities layer is extended by the service discovery module that has the role to enable interaction between objects that are friends.
It can retrieve an information about the real world posted in the server by a friend or can find a specific service provided by another vehicle/RSU.

36. Experimental Evaluation
we used a dataset generated by SUMO (Simulation of Urban MObility).
SUMO is an open source traffic simulator designed for road networks of large cities, by mean of which it is possible to generate traces of people mobility and every type of vehicle (cars, buses trucks etc.)
we used an existing traffic model for the city of Cologne.
The considered dataset was related to around 10,000 vehicles.

37. Experimental Evaluation
Assuming vehicles with p interfaces, we simulated the establishing of SOR type relationships for different intervals of visibility and for different distances.
This type of relationship depends on the extent of time two vehicles stay in contact, and usually when vehicles are still in a jam next to traffic lights.

38. Experimental Evaluation
CWOR is another relationship that depends on node movements, but it requires the availability of information about the position of RSUs that are not in the model yet.
For this reason, we have decided to proceed with SORs only.

39. Experimental Evaluation
Numbers of vehicles
10000
Visibility range
100, 150, 200, 250
Visibility interval
30, 45, 60, 75, 90(sec)
Network protocol
802.11p
Table of simulation configuration
Fig. 4. Giant Component for different visibility ranges and different visibility intervals

40. Conclusions 본 논문은 VANET 환경을 IoT와 연계함
차량에 인터넷이 가능한 광역통신(3G) 환경과 ad-hoc network 환 경을 함께 적용하여 효율적인 VANET 환경을 추구함.
또한 IoT를 연계하기 위한 VANET용 middle ware를 제안함.
본 논문은 SOR, 즉 V2V의 성능만을 평가함.
차량의 visibility range가 150m이상일 때 신뢰성 있는 Giant Component가 생성됨을 확인함.