• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.6
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• pp.225-230
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• 2015

This study presents a method for generating IEC 61850 Sampled Values(SV) traffic by combining the emulation function of network simulator ns-3 with the actual communication equipment. For the SV traffic generation and reception, the emulation function of the network simulator ns-3 is used, while as a communication network, the actual communication equipment, switches are used. In addition, the SV traffic frames generated are analyzed, using Wireshark, and it is confirmed that the SV traffic frames are generated accurately. The method for the SV traffic generation proposed in the present study will be very useful when various SV traffics are generated under the environment of an actual substation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2107-2113
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• 2015

This paper proposed a Prior Forecast System of Crossroad Traffic Information that allows vulnerable road users to perceive traffic signal changes beforehand and respond in concentrated traffic areas such as crossroads. Also, it mapped out information linking procedures of the proposed system and it designed a PHY based wireless communication simulator to verify the operational feasibility of wireless communications. Conclusively, by conducting performance analysis according to crossroad channel environments using the simulator designed in this paper, it verified that a Prior Forecast System of Crossroads Traffic Information service for vehicle IT based decision-making support for vulnerable road users is a possibility.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.1
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• pp.49-54
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• 2019

Since the underwater communication environment, which is used mainly in acoustic channel, is different from terestrial communication, it needs to analyze the appropriate transmission performance in underwater environment to implement the communication services. Appropriate traffic process method for a communication service is required through transmission performance of object traffic for the communication service. In this paper, transmission performance of video traffic on underwater MANET(Mobile Ad-hoc Network) is analyzed and video traffic configuration scheme on underwater MANET with results of performance analysis is suggested, This study is done with computer simulation based on NS(Network Simulator)-3. throughput, transmission delay, packet loss rate is used for transmission performance.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.155-164
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• 2008

Variable Message Signs (VMS) is one of the major components for Intelligent Transport Systems (ITS) services that provides real-time traffic and incident information to drivers. The objective of this research was to develop a method determining the optimal location of VMS considering safety and driving characteristics of various drivers. A driving simulator was utilized to evaluate how drivers can safely exit to off-ramp depending on various VMS locations while information relating route diversion was provided. The binary logistic regression and factor analysis were applied in developing a probability model that predicts the success of safe off-ramp exiting. Based on the developed probability model, a method to estimate the spacing between VMS and off-ramp is suggested. It is expected that the products of this study would be utilized as a tool in determining VMS locations for ITS planners and designers.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.59-67
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• 2011

It can prevent traffic accidents in a way as taking precautionary measures for road safety at signalized intersection in advance. Particularly, traffic accidents can be reduced at relatively low cost without redesigning alignments. That is 'Positive Guidance method' which can help prevent traffic accidents through improvement of road facilities at signalized intersection. In this study, potentially higher hazardous signalized intersection due to speeding was selected through site investigation. Field analysis at designated section was conducted and devised a plan for improvements of road facilities. Subjects drove in driving simulator in 3-D virtual reality of designated intersection. Based on data from simulator, statistical analysis(t-verification) was conducted for 'Before and After effectiveness' of speed reduction. As a result, it indicates that speed reduction was effective after improvements at each spot in driving simulator. In the future, hazardous signalized intersections which can be applied for PG method will be effective for road safety based on this research.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.58-65
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• 2001

Many changes in the railway environment has directly affected to the railway company. To cope immediately with the influence of environment and to promote productivity, the railway company has to introduce an efficient train operation system and related core technologies. The railway system is composed or large-scale infrastructures ann high-cost trains. Simulation method is one or core technologies and also is efficient tool for planning and analyzing this kind of complex system. The purpose of this research is to develop multi-train traffic simulator considering high-speed train for GyongBu-Line. To achieve this objective, the elements of railway system was analyzed, and as a result, a data structure modeling for the railway system such as rail-Tine infrastructure, rain, timetable and operational route is presented. The developed simulator is composed of three major part : input-module, main-module, and output module. The concept and brief explanation of each module will be treated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.5
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• pp.1109-1116
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• 2010

In this paper, some performance characteristics of VoIP(Voice over Internet Protocol) for MANET(Mobile Ad-hoc Networks) with simulation is studied and appropriate condition for implementation of VoIP service is suggested. VoIP simulator is implemented with NS(Network Simulator)-2. VoIP traffic for simulation is generated with some codecs of G.711, G.723.1, G.726-32, G.729A, GSM.AMR and iLBC. As simulation results for traffic transmission under $670{\times}670m$ 50node MANET environment, performance data for MOS(Mean Opinion Score), network delay, packet loss rate and transmission bandwidth are measured. Normalized analysis about measured results shows that maximum VoIP connection satisfying VoIP service quality condition is 15.

• Asian Journal of Innovation and Policy
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• v.11 no.1
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• pp.110-147
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• 2022

Many megacities are exposed to natural hazards such as earthquakes, and when located in coastal regions, are also vulnerable to hurricanes and tsunamis. The physical infrastructures of transportation systems in megacities have become so complicated that very few organizations can understand their response to extreme events such as earthquakes and can effectively mitigate subsequent economic downfalls. The technological advances made in recent years to support these complex systems have not grown as fast as the rapid demand on these systems burdened by population shift toward megacities. The objective of this paper is to examine the risks imposed on and recoveries of transportation systems in megacities as the result of extreme events such as an earthquake. First, the physical damage to transportation infrastructure, loss of the transportation system performance, and the corresponding economic loss from disruptions to passenger and freight traffic is evaluated. Then, traffic flows are re-routed to reduce vehicles' delay due to earthquakes using a microscopic traffic flow simulator with an optimization model and macroscopic terminal simulator. Finally, the economic impact of the earthquake is estimated nationwide. Southern California is regarded as the region of study. The results demonstrate the effectiveness of the integrated model and provide what and how to prepare innovative resilience policies of urban infrastructure for a natural disaster occurrence.

• The Transactions of the Korea Information Processing Society
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• v.7 no.4
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• pp.1217-1226
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• 2000

Traditionally, Mobile Teletraffic model consists of two sub-models, i.e. the network traffic model and the traffic source model. In this paper, we present the traffic source model by developing MobCall (Mobile Call Simulator) which analyses various mobile wireless environments based on regional characteristics that the base stations are located. User mobility is presented by regional average vehicle speeds and the transportation share rate. Moreover, the user mobility on subway, which is increasing in urban area, is considered in MobCall. And also, user's movements on highway are considered in MobCall. The object-oriented simulation platform, C++SIM, is used to implement MobCall. Using MobCall, the accumulated number of calls in residential and commercial regions, the handoff rate with respect to traffic sources of Seoul, the handoff rate on highway, and the handoff rate according to the call duration are presented. MobCall enables the simulation of dynamic handoff buffering and functional entity control of one base station according to the changes in user's calling pattern at the design phase. Also, when a new town is under construction by a detailed plan, MobCall is used to design the mobile network with regional characteristics and user mobility considered.

• International Journal of Highway Engineering
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• v.19 no.5
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• pp.163-171
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• 2017

PURPOSES : Traffic safety facilities are used to prevent traffic accidents before they occur by providing drivers with information on traffic situations and the geometric design of roads. However, some facilities not defined in guidelines do not meet installation criteria, yet are being installed and used in order to increase efficiency in traffic flow and prevent traffic accidents in a specific expressway zone. In this study, we have evaluated the effect of delineation system which are not defined in the guideline criteria. METHODS : Different virtual scenarios were created for roads using expressway median barrier chevron signs, with a driving simulator used to evaluate the installation and operational effect of such signs. Ten experiments were performed with left- and right-curved roads at curve radius intervals of 500 m, from 500 m to 2,500 m. RESULTS : For sections with a curve radius of more than 1,500 m, drivers had a clear tendency toward stable driving regardless of delineation system. When a chevron sign is installed on a protection fence in the road curving left, an expanded installation is recommended up to the section with a curve radius of 1,000 m. According to the analysis results for the RHB (Relative High Beta spectrum), driving concentration also improved up to a curve radius of 1,000 m. CONCLUSIONS :The experiment result indicates the extent of biasing within a lane and the manipulation amount of steering handle, were analyzed and found to be affected by curve radius and road alignment regardless of delineation system.