阅读说明：本技术 一种结合实体信任和社交信任的车辆信任评估方法 (Vehicle trust evaluation method combining entity trust and social trust ) 是由 邱铁 赵颖颖 陈宁 张朝昆 周晓波 于 2021-01-13 设计创作，主要内容包括：本发明属于车联网的技术领域,具体涉及一种结合实体信任和社交信任的车辆信任评估方法,本发明包括对信任分级的目的是激励用户共同维护网络的可靠性和安全性,不同级别的功能可以激发用户对路况通告做出更正确的响应,从而使车辆能够更快,更可靠地获得实际交通信息,在社交车联网中,司机的驾驶情绪很重要,智能交通最终目标是使驾驶员或乘客拥有舒适的旅程,信任激励制度还可以减少干扰信息的传播并提供舒适的环境。本发明能够提高社交车联网的信息可靠性和安全性,为出行提供更舒适的方式,还结合实体信任和社交信任,降低恶意信息的传播率,提高对恶意车辆的检测率。(The invention belongs to the technical field of vehicle networking, and particularly relates to a vehicle trust evaluation method combining entity trust and social trust. The invention can improve the information reliability and safety of the social networking service, provides a more comfortable way for traveling, and also combines the entity trust and the social trust to reduce the spread rate of malicious information and improve the detection rate of malicious vehicles.)

1. A vehicle trust evaluation method combining entity trust and social trust is characterized by comprising the following steps:

the method comprises the following steps: judging entity trust according to historical communication between vehicles, judging whether the vehicles have historical direct communication, and obtaining the direct trusty ratio between the vehicles;

step two: when any vehicle P enters the communication range of the roadside unit, the P sends the trust values IT of all the neighbor vehicles Q which are indirectly or directly communicated with the P to the roadside unit, and the roadside unit passes through a formula;

wherein, CT_QNeighbor vehicle P representing roadside unit junction Q₁,P₂…P_iThe trust value of Q obtained by the trust value report is totally evaluated;represents P_i-an indirect trustable ratio of Q; then combine each P₁，P₂…P_iAnd performing total evaluation on the Q value by the trust value sent by the vehicle, and reporting to the cloud.

Step three: the value range of the vehicle trust ratio value CT is 0< CT < 1, and the CT of each vehicle reported by the roadside unit is multiplied by 100 to obtain entity trust;

step four: recommending social relationships within the communication range to the vehicles according to the interest list similarity or common destination of each vehicle;

step five: vehicles with two or more social relationships established within the delta t time are defined as old friends, the old friends can score the social behaviors of each other, and the returned total social trust is obtained by the following formula

Wherein, score_jiThe score of the vehicle j on the social behavior of the vehicle i is shown, N represents that N vehicles and the vehicle i establish a social relationship more than twice in the delta t time, and alpha is a sliding factor.

2. The vehicle trust evaluation method in combination with entity trust and social trust of claim 1, wherein the step of using the credit evaluation for V2V zoning communication is as follows:

the vehicle density is monitored at the cloud end, the vehicles are uniformly distributed in each area, and the sizes of the areas meet the relation of

Wherein, B_iAnd B_i+1(i ∈ {0, 1, 2. }) represents two boundary positions of the (i +1) th region of the road; d (x) represents a cloud detected vehicle density function; δ represents an error range;

the size of the region is adjusted by taking U as a unit length of 5m, so that the proportion of the number of the distrusted vehicles in each region to the total number satisfies the formula

Wherein, Num (T)_low) Representing the total number of distrusted vehicles in the area and Num All representing the total number of vehicles in the area.

3. The vehicle trust evaluation method combining entity trust and social trust of claim 1, wherein the step one comprises:

if vehicles M and N have historical direct communication, then this may be by formulaObtaining a direct trustable ratio between M and N;

wherein R is_MNRepresenting a frequency of trusted communication between M and N; ALL_MNIs to represent the total communication frequency between M and N;

if there is no historical direct communication between vehicles A and B, then C exists_iIs an intermediate vehicle, between A and B, passing C_iIndirectly communicate through a formulaObtained between A and BThrough C_iThe indirect trustable ratio of;

wherein the content of the first and second substances,is between A and B through C_iAn indirect trust ratio;andis a-C obtained from the formula_iAnd C_iB direct trustful ratio.

4. The vehicle trust evaluation method in combination with entity trust and social trust of claim 3, further comprising:

vehicle A and B can trust the ratio IT through indirect communication of all intermediate vehicles C_ABCan be represented by formula

So as to obtain the compound with the characteristics of,

wherein, C₁,C₂…C_iAnd combining the indirect credible proportions of each intermediate vehicle for each intermediate vehicle C passed by the indirect communication of the A and the B to form the overall credible proportions of the A and the B.

5. The vehicle trust evaluation method in combination with entity trust and social trust of claim 1, wherein the fourth step comprises:

more new friends are considered to have social activity within a preset time, and the social activity of the vehicle is calculated according to the formula

Wherein N is_i(t- Δ t) represents a social relationship list established by vehicle i at time (t- Δ t), N_i(t) represents the social relationship list established by vehicle i at time (t), SA_iThe change of the newly established social relationship of the vehicle i at the time t is represented as the social activity of the vehicle.

6. The vehicle trust evaluation method in combination with entity trust and social trust of claim 1, wherein: in the fourth step, the evaluation of social trust includes considering user interests, social activity, and social relationships.

Technical Field

The invention belongs to the technical field of vehicle networking, and particularly relates to a vehicle trust evaluation method combining entity trust and social trust.

Background

Social networking over vehicles (SIoV) is a follower of the internet of things and is the core of intelligent transportation systems. Over the past few decades, the explosive increase in the number of vehicles on roads has exacerbated traffic congestion in all major cities in the world. It brings a series of problems to traffic such as information congestion, transmission delay and increase of untrustworthy vehicles. In SIoV, each vehicle is considered an intelligent communication system, equipped with a powerful multi-sensor platform, highly mobile wireless communication devices and a computing unit. SIoV integrates people's social activities into the physical internet of vehicles, mainly for providing more reliable services, such as driving safety, traffic efficiency optimization, data collection, advertising, entertainment, social activities and comfort improvement. The V2V transfer occurs in a less than fully secure and trusted environment. Human social factors are the main reason for incomplete trust in the network. Malicious acts such as the transmission of erroneous traffic messages and interfering advertisements can disrupt the normal operation of the network. Poor behaviors such as equipment damage, information privatization, false news and interference cause poor comfort of a low content reception rate trip.

Trust evaluations have proven reliable in enhancing network reputation. In our daily network life, trust is used to maintain the normal operation of the network. For example, applications such as online games, payees, microblogs, etc. classify users according to a confidence level. Users with high trust have more application functionality than users with low trust, and users with low trust will be blacklisted. To address the trust issue, in SIoV, the vehicle performs different operations depending on the trust level, thereby motivating the user to maintain better behavior. When the vehicle is always performing well and getting a high degree of trust, it can use all application functionality. Such as one that utilizes a method of earning a token to incentivize people in the network to actively forward vehicle announcements. The scheme can improve the enthusiasm and the effectiveness of network activities, but lacks quantitative evaluation on trust, so that malicious vehicles are easy to ignore.

In social networking, a trust evaluation for a vehicle requires a combination of entity trust and social trust. Wherein the entity trust is mainly related to the communication capability of the vehicle equipment (such as the vehicle-mounted unit equipment, the antenna, the processing unit and the receiving and transmitting unit), and the entity trust is the evaluation of the communication success rate of the vehicle. Social trust is subjective trust dominated by the social behavior of people and is important for determining and maintaining the overall reliability of SIoV. Adverse behaviors such as equipment damage, malicious information, and interfering advertisements can disrupt the normal operation of the network. Such bad behavior may affect the reliability and security of the network, destroy comfort during driving, and cause road congestion and traffic paralysis.

Disclosure of Invention

The invention aims to: aiming at the defects of the prior art, the vehicle trust evaluation method combining entity trust and social trust is provided, the information reliability and safety of social vehicle networking are improved, a more comfortable mode is provided for traveling, the propagation rate of malicious information is reduced by combining the entity trust and the social trust, and the detection rate of malicious vehicles is improved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a vehicle trust evaluation method combining entity trust and social trust comprises the following steps:

the method comprises the following steps: judging entity trust according to historical communication between vehicles, judging whether the vehicles have historical direct communication, and obtaining the direct trusty ratio between the vehicles;

step two: when any vehicle P enters the communication range of the roadside unit, the P sends the trust values IT of all the neighbor vehicles Q which are indirectly or directly communicated with the P to the roadside unit, and the roadside unit passes through a formula;

wherein, CT_QRepresenting roadside units in combination with QNeighbor vehicle P₁,P₂…P_iThe trust value of Q obtained by the trust value report is totally evaluated;represents P_i-an indirect trustable ratio of Q; then combine each P₁，P₂…P_iAnd performing total evaluation on the Q value by the trust value sent by the vehicle, and reporting to the cloud.

Step three: the value range of the vehicle trust ratio value CT is 0< CT < 1, and the CT of each vehicle reported by the roadside unit is multiplied by 100 to obtain entity trust;

step four: recommending social relationships within the communication range to the vehicles according to the interest list similarity or common destination of each vehicle;

step five: vehicles with two or more social relationships established within the delta t time are defined as old friends, the old friends can score the social behaviors of each other, and the returned total social trust is obtained by the following formula

Wherein, score_jiThe score of the vehicle j on the social behavior of the vehicle i is shown, N represents that N vehicles and the vehicle i establish a social relationship more than twice in the delta t time, and alpha is a sliding factor.

As an improvement of the vehicle trust evaluation method combining entity trust and social trust, the steps of using the credit evaluation for V2V subarea communication are as follows:

the vehicle density is monitored at the cloud end, the vehicles are uniformly distributed in each area, and the sizes of the areas meet the relation of

Wherein, B_iAnd B_i+1(i ∈ {0, 1, 2. }) represents the (i +1) th roadTwo boundary positions of the region; d (x) represents a cloud detected vehicle density function; δ represents an error range;

the size of the region is adjusted by taking U as a unit length of 5m, so that the proportion of the number of the distrusted vehicles in each region to the total number satisfies the formula

Wherein, Num (T)_low) Representing the total number of distrusted vehicles in the area and Num All representing the total number of vehicles in the area.

As an improvement of the vehicle trust evaluation method combining entity trust and social trust, the first step includes:

the method is characterized in that:

if vehicles M and N have historical direct communication, then this may be by formulaObtaining a direct trustable ratio between M and N;

wherein R is_MNRepresenting a frequency of trusted communication between M and N; ALL_MNIs to represent the total communication frequency between M and N;

if there is no historical direct communication between vehicles A and B, then C exists_iIs an intermediate vehicle, between A and B, passing C_iIndirectly communicate through a formulaObtaining a passage C between A and B_iThe indirect trustable ratio of;

wherein the content of the first and second substances,is between A and B through C_iAn indirect trust ratio;andis a-C obtained from the formula_iAnd C_iB direct trustful ratio.

As an improvement of the vehicle trust evaluation method combining entity trust and social trust, the invention further includes:

vehicle A and B can trust the ratio IT through indirect communication of all intermediate vehicles C_ABCan be represented by formula

To obtain

Wherein, C₁,C₂…C_iAnd combining the indirect credible proportions of each intermediate vehicle for each intermediate vehicle C passed by the indirect communication of the A and the B to form the overall credible proportions of the A and the B.

As an improvement of the vehicle trust evaluation method combining entity trust and social trust described in the present invention, in the fourth step, the method includes:

more new friends are considered to have social activity within a preset time, and the social activity of the vehicle is calculated according to the formula

Wherein N is_i(t- Δ t) represents a social relationship list established by vehicle i at time (t- Δ t), N_i(t) represents the social relationship list established by vehicle i at time (t), SA_iThe change of the newly established social relationship of the vehicle i at the time t is represented as the social activity of the vehicle.

In the fourth step, the evaluation of social trust includes considering user interests, social activity and social relationships.

The invention has the advantages that the trust grading aims at stimulating users to maintain the reliability and the safety of the network together, the functions of different grades can stimulate the users to make more correct response to road condition notifications, so that the vehicles can obtain actual traffic information more quickly and reliably, in the social networking, the driving emotion of drivers is very important, the final goal of intelligent traffic is to enable drivers or passengers to have comfortable journey, the trust incentive system can also reduce the spread of interference information and provide comfortable environment, and the region division rule transmitted by V2V is based on the position and the trust of the vehicles, so that the trust evaluation model has better practical significance. The social networking service system and the social networking service method can improve the information reliability and safety of the social networking service and provide a more comfortable way for traveling; in addition, the invention combines entity trust and social trust, reduces the spread rate of malicious information and improves the detection rate of malicious vehicles; the improved V2V partition rule of the invention improves the average content receiving rate.

Drawings

Features, advantages and technical effects of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a general architecture of a social networking service of the present invention.

FIG. 2 is a three example schematic diagrams of social trust evaluation of the present invention.

Fig. 3 is a schematic diagram of the improved partitioning rule under the extreme distribution condition of the distrusted vehicles.

Detailed Description

As used in the specification and in the claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect.

Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The present invention will be described in further detail with reference to fig. 1 to 3, but the present invention is not limited thereto.

The overall architecture of the social networking system is shown in fig. 1, and the roadside unit RSU and the on-board unit OBU can communicate with each other, and a social relationship can be established between vehicles. The social networking service is an environment which is not completely trusted, and the network can be attacked by untrusted vehicles to reduce the reliability of information, so that the comprehensive trust evaluation scheme combining entity trust and social trust is adopted.

An evaluation model comprising entity trust, which is mainly related to the communication capabilities of the vehicle devices (such as OBUs, antennas, processing units and receiving and transmitting units). The success or failure of the communication of the vehicle is not at the will of the person. Its main function is to assess the ability of the vehicle to correctly and immediately forward the content. The entity trust evaluation steps are as follows:

step 1: entity trust is judged from historical communications between vehicles. Assuming that vehicles M and N have historical direct communication, a direct trusty ratio between M and N can be obtained by equation (1):

in the formula, R_MNRepresenting between M and NA frequency of trusted communications; ALL_MNIs to represent the total communication frequency between M and N;

step 2: if there is no historical direct communication between A and B, then C exists_iIs an intermediate vehicle. Between A and B via C_iIndirect communication is performed. Thus, a C between A and B can be obtained by formula (2)_iThe indirect trustable ratio of.

Wherein the content of the first and second substances,is between A and B through C_iAn indirect trust ratio;andis A-C obtained from formula (1)_iAnd C_i-B direct trustable ratio;

and step 3: vehicle A and B can trust the ratio IT through indirect communication of all intermediate vehicles C_ABThis can be derived from formula (3):

in the formula, C₁,C₂…C_iIs each intermediate vehicle C through which the indirect communication of a and B passes. According to the invention, the indirect credible proportions of each intermediate vehicle are combined to form the overall credible proportions of A and B;

and 4, step 4: when any vehicle P enters the communication range of the RSU, the P sends the trust value IT of all the neighbor vehicles Q which have indirect communication or direct communication with the P to the RSU, and the RSU combines each P through the formula (4)₁,P₂…P_iAnd performing total evaluation on the Q value by the trust value sent by the vehicle, and reporting to the cloud.

In the formula, CT_QNeighbor vehicle P representing RSU combined with Q₁,P₂…P_iThe trust value of Q obtained by the trust value report is totally evaluated;represents P_i-an indirect trustable ratio of Q, obtained from equation (3);

and 5: the value range of the vehicle trust ratio value CT is 0< CT < 1, and the vehicle trust required by the invention is evaluated to be a constant within one hundred. The invention therefore multiplies the CT of each vehicle reported by the RSU by 100 to obtain entity trust.

Second, the evaluation of social trust also plays a major role in social car networking. Social trust, with human dominance, by drivers or passengers is an important factor in determining and maintaining the overall reliability of social car networking. The evaluation of social trust mainly considers three social characteristics of user interest, social activity and social relationship. The social trust evaluation steps are as follows:

step A: each vehicle stores its own interest list and social relationship list. The present invention recommends social relationships within a communication range to vehicles according to the interest list similarity or common destination of each vehicle. The vehicle may also autonomously choose whether to establish a social relationship with the vehicle. The high dynamics of the vehicles' neighbor list over time also determine the social relationship list for each time of the vehicle. Having more new friends to meet over a period of time is considered more socially active. Equation (5) is the social activity calculation for the vehicle:

in the formula, N_i(t- Δ t) represents a social relationship list established by vehicle i at time (t- Δ t), N_i(t) representsSocial relationship list, SA, established by vehicle i at time (t)_iRepresents the change in social relationship established by vehicle i at time t, here represented by the social activity of the vehicle;

and B: in addition to this, friends who remain in long-term and regular contact also take a major role in social trust evaluation, and vehicles that have established two or more social relationships within Δ t time are defined as old friends who can score each other's social behavior, and the total social trust returned is given by equation (6):

in the formula, score_jiThe score of the vehicle j on the social behavior of i is shown, N represents that the social relationship between N vehicles and the vehicle i is established more than twice in the time delta t, and alpha is a sliding factor, and fig. 2 shows examples of vehicles with three different levels of trust of the social trust evaluation.

The integrated trust evaluation is a weighted average of entity trust and social trust.

T＝μ*ET+θ*ST， (7)

The steps for applying the trust evaluation scheme to V2V split zone communication are as follows:

step a: and monitoring the density of the vehicles at the cloud end, and uniformly distributing the vehicles in each area. Region size satisfaction formula (8)

In the formula, B_iAnd B_i+1(i ∈ {0, 1, 2. }) represents two boundary positions of the (i +1) th region of the road; d (x) represents a cloud detected vehicle density function; δ represents an error range;

step b: the size of the region is adjusted by taking U as a unit length of 5m, so that the proportion of the number of the distrusted vehicles in each region to the total number satisfies the formula (9)

In the formula, Num (T)_low) Representing the total number of distrusted vehicles in the area, Num All representing the total number of vehicles in the area;

step c: when the number of untrusted vehicles in the area is extreme, the network temporarily considers an untrusted vehicle with trust close to 60 as a trusted vehicle, which may use the application function the same as the trusted vehicle, and at this point the road is re-divided to satisfy the conditions of equations (8) and (9), as shown in fig. 3.

Trust evaluation in the social networking service combines entity trust and social trust, and a trust level is distributed after an evaluation result is obtained, wherein the entity trust is evaluation on the success rate of historical communication and is related to the equipment capability of a vehicle; the evaluation of social trust is combined with social activity of new friends and trust feedback of old friends, the vehicle obtains the trust value of the vehicle from the RSU, and the application program function which can be used in the social vehicle networking is distributed according to the trust level, so that the driving behavior is standardized.

The application functions in the social networking service are divided into the following four points:

(1) receiving and forwarding information;

(2) responding to announcements of other vehicles;

(3) exchanging information in real time;

(4) and vehicles of the same hobbies or common destinations.

The vehicle is divided into four trust levels according to the trust evaluation, and the details of the trust levels are as follows:

a: t is more than or equal to 85 and less than or equal to 100, and the vehicle can use all four functions;

b: t is more than or equal to 70 and less than 85; vehicles can only perform the functions of (1), (2) and (3) because of the malicious social behaviors, and the safety of the social network is damaged;

c: vehicles with T <70 > of 60 ≦ will receive trust warnings, available functions are limited to (1) (2) protecting other vehicles from harassment, and messages issued by such vehicles may not be authentic;

d: t < 60; an untrusted vehicle; this indicates that the vehicle has performed many malicious social activities and many times ignored trust warnings, that the untrusted vehicle was pulled into a blacklist, will be temporarily deleted by the social networking service, and cannot perform any function other than (1).

The purpose of trust rating is to encourage users to maintain the reliability and security of the network together, and different levels of functionality can motivate users to respond more correctly to road condition announcements, so that vehicles can obtain actual traffic information more quickly and reliably. The trust incentive system can also reduce the spread of interference information and provide a comfortable environment, and the region division rule transmitted by the V2V is based on the position and trust of the vehicle, so that the trust evaluation model has better practical significance.

Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.