• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2309-2315
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• 2013

VANET(Vehicular Ad-hoc Network) is getting attention as an application to improve driver safety through inter-vehicle communication. For activation of VANET, privacy-preserving mutual authentication has to be guaranteed. In previous works, authors proposed various group-based authentication protocols. However, risks on ID exposure due to repeated use of group key and RSU(Road Side Unit) DoS attack were not considered. In this paper, we propose a probabilistic approach for robust anonymous authentication protocol. We evaluated our proposed method in a sets of criteria in VANET and verified it is an efficient solution for enhancing privacy.

• Proceedings of the KOR-KST Conference
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• 2007.05a
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• pp.399-408
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• 2007

Dedicated Short Range Communications(DSRC) is a block of spectrum in the 5.8GHz band. DSRC is the useful technology of ITS Service. Japan operates ETCS, VICS by DSRC technology and DSRC technology is used ETCS Standard in Korea. There are many kind of utilization of DSRC in ITS. This is a study for traffic information service and collection with DSRC. Traffic management server service traffic information to driving vehicle by RSE(Road Side Equipment). OBU(Onboard Unit) in vehicle send the information to PDA(Personal Digital Assistant). Client S/W show the information to driver by text, pictogram, sound and return PDA H/W ID to OBU. Server make section traffic information by the PDA H/W ID information.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.2
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• pp.239-248
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• 2012

VANET (Vehicular Ad-hoc Network) is a type of MANET (Mobile Ad-hoc Network) which is the next-generation networking technology to provide communication between vehicles or between vehicle and RSU (Road Side Unit) using wireless communication. In VANET system, a vehicle accident is likely to cause awful disaster. Therefore, in VANET environment, authentication techniques for the privacy protection and message are needed. In order to provide them privacy, authentication, and conditional, non-repudiation features of the group signature scheme using a variety of security technologies are being studied. In this paper, and withdrawal of group members to avoid frequent VANET environment is suitable for vehicles produced by the group administrator for a private signing key to solve the key escrow problem of a group signature scheme is proposed. We proposed a message batch verification scheme using Bloom Filter that can verify multiple messages efficiently even for multiple communications with many vehicles.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.1
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• pp.17-31
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• 2010

In VANET (Vehicular Ad hoc NETwork), vehicles can efficiently verify a large number of signatures efficiently using batch verification techniques. However, batch verification performed independently in each vehicle raises many redundant verification cost. Although, an RSU (Road Side Unit) can perform the batch verification as a proxy to reduce this cost, it additionally requires an efficient method to identify invalid signatures when the batch verification fails. In this paper, we analyze several ways of constructing a distributed batch verification system, and propose an efficient distributed batch verification system in which participating vehicles perform batch verification in a distributive manner for a small size signature set. In our proposed system, each node can report the batch verification result or the identified invalid signatures list and the RSU who received these reports can identify the invalid signatures and efficiently exclude them.

• The Journal of the Korea Contents Association
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• v.21 no.3
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• pp.68-79
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• 2021

On the Social Internet of Things (SIoT), social activities occur through which the vehicle generates a variety of data, shares them with other vehicles, and sends and receives feedbacks. In order to share reliable information between vehicles, it is important to determine the reliability of a vehicle. In this paper, we propose a vehicle trust evaluation scheme to share reliable information among vehicles. The proposed scheme calculates vehicle trust by considering user reputation and network trust based on inter-vehicle social behaviors. The vehicle may choose to scoring, ignoring, redistributing, etc. in the social activities inter vehicles. Thereby, calculating the user's reputation. To calculate network trust, distance from other vehicles and packet transmission rate are used. Using user reputation and network trust, local trust is calculated. It also prevents redundant distribution of data delivered during social activities. Data from the Road Side Unit (RSU) can be used to overcome local data limitations and global data can be used to calculate a vehicle trust more accurately. It is shown through various performance evaluations that the proposed scheme outperforms the existing schemes.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.2
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• pp.280-285
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• 2021

When VNDN technology is used as a communication technology for infotainment application services of connected vehicles, it is possible to realize data-centric networking technology in which data is the subject of communication.Vehicle security attacks and hacks, performance degradation during long-distance data transmission, and frequent data loss It is possible to innovate the limitations of the current host-oriented Internet-based infotainment application service technology of connected vehicles. The data packet forwarding issue to deliver critical information data that is very sensitive to delay in the VNDN on a push-based basis to RSU (Road Side Unit), etc. is one of the issues to be solved for realizing VNDN-based application services. We comprehensively analyze existing forwarding techniques to support push-based data traffic under the environment, and compare and analyze each technique in terms of performance.

• The Journal of the Korea Contents Association
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• v.22 no.5
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• pp.26-36
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• 2022

Recently, studies have been conducted to cluster vehicles and disseminate safety messages in a VANET environment for driver safety and smoothy traffic. This paper proposes cluster management scheme for safety message dissemination through V2V communication and V2I communication in a VANET environment with high vehicle density and mobility. The proposed scheme reduces packet loss by selecting CH considering reception quality, total data owned by vehicles, moving speed, and connected vehicles, and maintaining cluster head candidates, which are the main agents of message dissemination, considering frequent cluster departures and subscriptions. In addition, the proposed scheme reduces duplicate messages by utilizing clusters by collaborating with a Road side unit(RSU). To prove the excellence of the proposed scheme, various performance evaluations are performed in terms of message packet loss and the number of RSU processing requests. As a result of performance evaluation, the cluster management scheme proposed in this paper shows better performance than the existing scheme.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.12
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• pp.449-454
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• 2014

While the era of driverless car has come, Vehicular Ad hoc NETwork(VANET) is getting important. Original VANET has a limit that cannot use computation power, storage space of On Board Unit(OBU) installed in a vehicle efficiently. VANET cloud computing(VCC) solves the limit to focus on using abilities of each vehicle. This article proposes VCC architecture for supplementing user addition and initial cloud creation that have been researched insufficiently.

• Journal of the Korean Geotechnical Society
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• v.29 no.12
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• pp.5-10
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• 2013

Bearing capacity of a drilled shaft can be separated into side resistance and base resistance. But in domestic design procedure side resistance is usually underestimated compared with base resistance. Results of bi-directional test showed that measured side resistances in each different layers are larger than those evaluated from several suggested methods. In this study, measured side resistances in each different layer of drilled shafts installed in domestic sites are analyzed and compared with evaluated side resistances from the method using revised SPT N value. For weathered rock and soft rock layer, from which rock core can hardly be obtained, we suggested new evaluated methods using revised SPT N value instead of the method using uniaxial compressive strength of rock. Resuts showed that the ranges of side resistance of cohesive and non-cohesive layer are $f_s{\leq}5tf/m^2$ and $f_s{\leq}15tf/m^2$ respectively. Range of side resistance in weathered rock is $15tf/m^2$ < $f_s{\leq}50tf/m^2$ and that in soft rock $f_s{\geq}35tf/m^2$.

• Magazine of the Korean Society of Agricultural Engineers
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• v.24 no.4
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• pp.57-68
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• 1982

The paddy fiels slope located in Kangweon province Hwyongsung gun Gonggeun myon Shinchonri was considerably steep and so it was impossible to economically consolidate the field up to date. But for the porpose of farm mechanization, the field (32. 27ha) was consolidated by the auther under the assitance of the Ministry of Agriculture and Fishery and,;the Administration of Kangweon province. This paddy field consolidation was caused by the treatise on "Land-consolidation methods for farm mechanization in the steep-sloped paddy field", of which the auther is the same. The constrution was carried out from September, 1981 to April, 1982. During the 4esign and construction, some Peculiarities were found and discussed. That is, in design, besides the common condititions for a design, some special conditions were considered and written below; (1) The ranges of field slope in this design were 1/100-1/30. (2) Long sides of the land readjustment blocks must be arranged abreast contour line, and so they make the amount of cutting and banking decreased so as to take the maximum advantage of the configuration of the field. (3) In design, the main principles of dividing blocks were written below; i) First of all, long side of a block should be drawn straight abreast a contour line. ii) Long side of a block should arrange abreast contour line and make its length 100-150m, if not, l)reak the side in order to make a bended rectangle. iii) Length of a short side should be determinded within differences of elevation (0.6 -1. 2m) between the two adjacent blocks toward the normal to a contour line. iv) Length of a short side should be above 15m and the ratio of long and short side should be slso kept 1: (4-6). v) A new field surface leveling was determinded from the elevation which produce the least amount of cuttingand banking within the range of 0.6-1. 2m diffe rences of elevation between the two adjacent blocks. vi) In the course of dividing blocks with the same width along the line which was normal to a contour line, all blocks connot keep their shape in a retangle because of steep slope of the field and so on, and so it was also necessory to make some non-retanglar and small blocks such as a trianglar or trapezoidal shape, which was impossible to use some of farm machinery. But because this non-rectanglar and small blocks were divided, larger and many rectanglar blocks can be divided and construction cost can also be lowered. According to the conditions discussed above, the paddy field consolidation project designed and constructed. And the results of this study were obtained as below; (1) Three-forth of total cost of this paddy field consolidation was not construction cost, and these cost consist of land grading (1/4), road and canal construction cost (1/4) and the other cost (1/4) such as surveying or materials and 56 on. (2) The steeper the land slope, the greater cost was assigned for road and canal construction, and than land grading. (3) Curtailment of the road and canal construction cost depended on simplificating their strutures. (4) In the case of the land slopes were low, the land grading cost was high by 1: 1.4 in comparison with the road and canal construction cost, and conversely when the slops were steep, the road and canal construction cost was high by 1 : 5 in compa- rison with the land grading cost. (5) The densities of irrigation canal, drainage canal and trunk and branch road were 150. Sm/ha, 60. im/ha and 17. 4m/ha respectively. The density of irrigation canal of the area was high by 2 times in comparison with the average one of Kangweon Province, and the others were nearly the same. (6) Most farmers (above 85%) knew the effects of paddy field consolidation. The effects are; 1) Improvement of irrigation 2) Improvement of farm management 3) Improvement of transportarion 4) farm mechanization and 5) grouping of the scattered land. And the more farm modernization was accomplished by these projects, the more farmers wanted to live in their land. (7) In spite of the very steep sloped paddy field, the diminution rate of the net farm land caused by consolidation was 7.7% which was nearly the same as the one of Chulweon plain of Kangweon province. Land grading cost was 971, OOOwon/ha which was rather cheap by 13.2% than the one of Ghulweon plain, and unit construction cost was 5, 341, OOOwon/ha (included soil addition) which was also nearly the same as the one of Chulweon plain and FNFIA (The federation of national farmland improvement association).