• Journal of Korea Multimedia Society
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• v.19 no.7
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• pp.1159-1165
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• 2016

Traffic violations such as moving while the traffic lights are red have come from a simple omission to a premeditated act. The traffic control center cannot timely monitor all the cameras installed on the roads to trace and pursue those traffic violators. Modern vehicles are equipped and controlled by several sensors in order to support monitoring and reporting those kind of behaviors which some time end up in severe causalities. However, such applications within the vehicle environment need to provide security guaranties. In this paper, we address the limitation of previous work and present a secure and privacy preserving protocol for traffic violation reporting system in vehicular cloud environment which enables the vehicles to report the traffic violators, thus the roadside clouds collect those information which can be used as evidence to pursue the traffic violators. Particularly, we provide the unlinkability security property within the proposed protocol which also offers lightweight computational overhead compared to previous protocol. We consider the concept of conditional privacy preserving authentication without pairing operations to provide security and privacy for the reporting vehicles.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.35-44
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• 2017

PURPOSES: This study suggests a specific methodology for the prediction of road surface temperature using vehicular ambient temperature sensors. In addition, four kind of models is developed based on machine learning algorithms. METHODS : Thermal Mapping System is employed to collect road surface and vehicular ambient temperature data on the defined survey route in 2015 and 2016 year, respectively. For modelling, all types of collected temperature data should be classified into response and predictor before applying a machine learning tool such as MATLAB. In this study, collected road surface temperature are considered as response while vehicular ambient temperatures defied as predictor. Through data learning using machine learning tool, models were developed and finally compared predicted and actual temperature based on average absolute error. RESULTS : According to comparison results, model enables to estimate actual road surface temperature variation pattern along the roads very well. Model III is slightly better than the rest of models in terms of estimation performance. CONCLUSIONS : When correlation between response and predictor is high, when plenty of historical data exists, and when a lot of predictors are available, estimation performance of would be much better.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5513-5529
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• 2016

Doppler Effect is a prominent obstacle in vehicular networks, which dramatically increase the Bit-Error-Rate (BER). This problem is accompanied with the presence of the Orthogonal Frequency Division Multiplexing (OFDM) systems in which the Doppler shift interrupts the subcarriers orthogonality. Additionally, Inter-Symbol Interference (ISI) and high Peak-to-Average Power Ratio (PAPR) are likely to occur which corrupt the received signal. In this paper, the single-carrier combined with the frequency domain equalizer (SC-FDE) is utilized as an alternative to the OFDM over the IEEE 802.11p uplink vehicular channels. The Minimum Mean Squared Error (MMSE) and Zero-Forcing (ZF) are employed in order to study the impact of these equalization techniques along with the SC-FDE on the propagation medium. In addition, we aim to enhance the BER, improve the transmitted signal quality and achieve ISI and PAPR mitigation. The proposed schemes are investigated and we found that the MMSE outperforms the ZF equalization under different Doppler shift effects and modulations.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.1-9
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• 2007

Compressed natural gas (CNG) has been used as a vehicular fuel compressed at 24.8 MPa because the energy density of natural gas is extremely low compared with gasoline. Thus it has problems in both safety and cost for multiple stage compression. For these reasons the use of adsorbed natural gas (ANG) has been pursued since the storage of natural gas is possible at a relatively low pressure. The present target is to obtain media to store natural gas at 3.5 MPa as ANG that ensures the comparable energy density of CNG, giving approximately one-fourth the driving range of an equivalent volume gasoline tank. In this review, the recent development of carbon media, their characteristics, and practical applications for natural gas storage are introduced and some recommendations are also suggested.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.1
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• pp.27-34
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• 2018

Various messages generated in vehicles are transmitted based on the wireless telecommunication which is a core technology of vehicle to everything (V2X). However, the hackers attack them upon penetration to the system and network to cause the generation of users' inconveniences for vehicular communication. Moreover, huge damage could be occurred in terms of physical and materialistic areas if the users in the vehicles were attacked in the communication environment. Therefore, this study was to design the safe communication protocol using hash tree technique in the V2X environments. Using hash tree technique, processes of issuing certificate and registration and communication protocol were designed, and safety analysis was performed on the attacking technique which is occurred in the existing vehicles. Approximately 62% of decrease in the capacity analysis was found upon comparative analysis of telecommunication processes with the system to issue the certificate which is used in the existing vehicles.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.12
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• pp.6121-6144
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• 2019

Numerous privacy-preserving authentication schemes have been proposed but vehicular ad hoc networks (VANETs) still suffer from security and privacy issues as well as computation and communication overheads. In this paper, we proposed a robust conditional privacy-preserving authentication scheme based on pseudonym root with cuckoo filter to meet security and privacy requirements and reduce computation and communication overheads. In our proposed scheme, we used a new idea to generate pseudonyms for vehicles where each on-board unit (OBU) saves one pseudonym, named as "pseudonym root," and generates all pseudonyms from the same pseudonym. Therefore, OBU does not need to enlarge its storage. In addition, the scheme does not use bilinear pairing operation that causes computation overhead and has no certification revocation list that leads to computation and communication overheads. The proposed scheme has lightweight mutual authentication among all parties and just for once. Moreover, it provides strong anonymity to preserve privacy and resists ordinary attacks. We analyzed our proposed scheme and showed that it meets security and privacy requirements of VANETs and is more efficient than traditional schemes. The communication and computation overheads were also discussed to show the cost-effectiveness of the proposed scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.7
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• pp.605-611
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• 2013

If an accident vehicle propagates emergency messages to other vehicles close to it, the other drivers may realize and avoid the accident spot. In this letter, we propose a broadcast scheme to propagate emergency messages fast in urban VANETs (Vehicular Ad-Hoc Networks) with the help of GPS (Global Position System). In our scheme, a transmitting vehicle chooses the farthest node as the next relay vehicle to propagate emergency messages. And, we suggest an algorithm for intersection recognition and SCF (Store-Carry-Forward) task by taking advantage of periodic hello packets to reduce the propagation time and enhance the delivery ratio.

• ETRI Journal
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• v.41 no.6
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• pp.703-714
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• 2019

Many use cases have been presented on providing convenience and safety for vehicles employing wireless access in vehicular environments and long-term evolution communication technologies. As the 70-MHz bandwidth in the 5.9-GHz band is allocated as an intelligent transportation system (ITS) service, there exists the issue that vehicular communication systems should not interfere with each other during their usage. Numerous studies have been conducted on adjacent interfering channels, but there is insufficient research on vehicular communication systems in the ITS band. In this paper, we analyze the interference channel performance between communication systems using distribution functions. Two types of scenarios comprising adjacent channel interference are defined. In each scenario, a combination of an aggressor and victim network is categorized into four test cases. The minimum requirements and conditions to meet a 10% packet error rate are analyzed in terms of outage probability, packet error rate, and throughput for different transmission rates. This paper presents an adjacent channel interference ratio and communication coverage to obtain a satisfactory performance.

• ETRI Journal
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• v.37 no.5
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• pp.867-876
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• 2015

This paper proposes an efficient interference control scheme for vehicular moving networks. The features of the proposed scheme are as follows: radio resources are separated into two resource groups to avoid interference between the cellular and vehicle-to-vehicle (V2V) links; V2V links are able to share the same radio resources for an improvement in the resource efficiency; and vehicles can adaptively adjust their transmission power according to the interference among the V2V links (based on the distributed power control (DPC) scheme derived using the network utility maximization method). The DPC scheme, which is the main feature of the proposed scheme, can improve both the reliability and data rate of a V2V link. Simulation results show that the DPC scheme improves the average signal-to-interference-plus-noise ratio of V2V links by more than 4 dB, and the sum data rate of the V2V links by 15% and 137% compared with conventional schemes.

• Convergence Security Journal
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• v.13 no.4
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• pp.47-52
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• 2013

VANET(Vehicular Ad-hoc Network) is a kind of ad hoc networks which is consist of intelligence vehicular ad nodes, and has become a hot emerging research project in many fields. It provides traffic safety, cooperative driving and etc. but has also some security problems that can be occurred in general ad hoc networks. In VANET, it has been studies that group signature method for user privacy. However, among a group of group key generation phase and group key update phase, RSU(Road-Side Unit) and the computational overhead of the vehicle occur. In this paper, we propose an efficient group key management techniques with CBF(Counting Bloom Filter). Our group key management method is reduced to the computational overhead of RSU and vehicles at the group key generation and renewal stage. In addition, our method is a technique to update group key itself.