• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1426-1437
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• 1999

The introduction of fast packet switching networks such as the ATM leads to the possibility of video services with constant quality. However, the fixed traffic descriptor(TD), which is defined by ATM Forum and ITU-T, can not simultaneously satisfy network efficiency and video quality. This paper presents fast resource reallocation protocol (FRRP) which can provide an effective compromise between network efficiency and video quality. This protocol reallocates the network resources and then adapts the traffic to the reallocated resources. In the proposed method, a video session is divided into several time-intervals according to its generated traffic and TD is calculated which well characterizes the traffic during the specific subdivided interval. In addition, a system model, where MPEG coding algorithm and network control are unified, is proposal and the performance of the FRRP in terms of cell loss rate(CLR) is evaluated though the simulation using real video traffic(Star Wars). Simulation results show that the FRRP has only 5 ~35% CLR of the fixed TD.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.3
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• pp.11-19
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• 2009

At present, an intelligent transport system (ITS) is being actively introduced as an alternative plan to solve various transport problems, and a traffic information provision service, a field of ITS, is being provided to users through diverse media. However, the evaluation of how useful the traffic information provided to the road users is limited to a simple questionnaire, and the systematic evaluation about what factors affect the usefulness of traffic information has not been realized. Therefore, it is impossible to calculate user convenience occurring due to traffic information, This paper aimed to develop an index to evaluate user satisfaction levels with traffic information and develop a user satisfaction level model. A result of establishing a user satisfaction level model by executing a questionnaire survey for the analysis object of variable message sign (VMS), a representative information provision medium, showed that 'desire satisfaction', 'trust', 'understanding', and 'efficiency' have an effect. Of them, the 'understanding' showed the highest level, so it was seen that, in case of VMS, how easily the character, figure, expression, etc. provided in the information was understood by users has the biggest effect on the satisfaction level of the information. The next levels of effects on the satisfaction was in the order of 'user trust', 'efficiency', and 'desire satisfaction'.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.69-72
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• 2007

In this paper, we analyze the performance of the network management system with intelligent mobile agent system. The proposed system dynamically selects appropriate its destinations. Thus, the system has an advantage of flexible network management in mobile network environments as well as dynamic change of traffic. Comparing its delay and throughput performance with the conventional SNMP based network management system, we find that the proposed mobile agent system performs better efficiency than the conventional one.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.40-48
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• 2006

In this paper, we propose the EPTS(Emergency vehicle Priority Transit system) for a rapid drive or emergency vehicles at the crossroads. The EPTS is one part of real-time traffic management system in the advanced traffic management system. The EPTS needs the connection or a traffic control system and a DSRC system. It can be applied to the real traffic situation considered with other traffic elements. As the result it is possible for the EPTS to nonstop drive because it induces an efficient drive of emergency vehicles. It is also relatively safe at the crossroad, it is expected that the EPTS is suitable for a telematics service which values efficiency above everything else.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.519-526
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• 2016

As marine accidents happen frequently, it is required to establish a marine traffic monitoring system, which is designed to improve the safety and efficiency of navigation in VTS (Vessel Traffic Service). For this aim, recently, X-band marine radar is used for extracting the sea surface information and, it is necessary to retrieve wave information correctly and provide for the safe and efficient movement of vessel traffic within the VTS area. In this paper, three different current estimation algorithms including the classical least-squares (LS) fitting, a modified iterative least-square fitting routine and a normalized scalar product of variable current velocities are compared with buoy data and then, the iterative least-square method is modified to estimate wave information by improving the initial current velocity. Through several simulations with radar signals, it is shown that the proposed method is effective in retrieving the wave information compared to the conventional methods.

• The Journal of Information Systems
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• v.29 no.2
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• pp.131-147
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• 2020

Purpose The purpose of this study is to develop intelligent vehicle parking distribution system based on LoRa network at the circumstance of traffic congestion during cultural festival in a local city. This paper proposes a parking dispatch and distribution system using a Q-learning algorithm to rapidly disperse traffics that increases suddenly because of in-bound traffics from the outside of a city in the real-time base as well as to increase parking probability in a parking lot which is widely located in a city. Design/methodology/approach The system get information on realtime-base from the sensor network of IoT (LoRa network). It will contribute to solve the sudden increase in traffic and parking bottlenecks during local cultural festival. We applied the simulation system with Queuing model to the Yudeung Festival in Jinju, Korea. We proposed a Q-learning algorithm that could change the learning policy by setting the acceptability value of each parking lot as a threshold from the Jinju highway IC (Interchange) to the 7 parking lots. LoRa Network platform supports to browse parking resource information to each vehicle in realtime. The system updates Q-table periodically using Q-learning algorithm as soon as get information from parking lots. The Queuing Theory with Poisson arrival distribution is used to get probability distribution function. The Dijkstra algorithm is used to find the shortest distance. Findings This paper suggest a simulation test to verify the efficiency of Q-learning algorithm at the circumstance of high traffic jam in a city during local festival. As a result of the simulation, the proposed algorithm performed well even when each parking lot was somewhat saturated. When an intelligent learning system such as an O-learning algorithm is applied, it is possible to more effectively distribute the vehicle to a lot with a high parking probability when the vehicle inflow from the outside rapidly increases at a specific time, such as a local city cultural festival.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.4
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• pp.107-117
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• 2008

OBE(On Board Equipment) of IR(Infrared)/RF(Radio Frequence)-DSRC(Dedicated Short Range Communication) are set up 1.25 million cars because Korea Highway Cooperation supplied in HiPass(Domestic Electronic Toll Collection System). But this DSRC system has strength and weakness of service for BIS(Bus Information System) or UTIS(Urban Traffic Information System) because BIS and UTIS are required vary high communication's performance and management. In this paper, Efficiency of IR/RF-DSRC is analyzed performance of MAC(Medium Access Control) by computer simulation for services of BIS or UTIS, so Suggested to be commensurated with medium of there service. Specially, DSRC is needed high mobility and throughput in the vary short communication range, so Analysed the transmission rate of data in each communication medium over the specific character of the MAC frame.

• Journal of Korea Society of Digital Industry and Information Management
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• v.5 no.4
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• pp.87-97
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• 2009

Internet network routing system is used to prevent spread and distribution of malicious data traffic. This study is based on analysis of diagnostic weakness structure in the network security domain. We propose an improved integrated multi-level protection domain for in the internal route of groupware. This paper's protection domain is designed to handle the malicious data traffic in the groupware and finally leads to lighten the load of data traffic and improve network security in the groupware. Infrastructure of protection domain is transformed into five-stage blocking domain from two or three-stage blocking. Filtering and protections are executed for the entire server at the gateway level and internet traffic route ensures differentiated protection by dividing into five-stage. Five-stage multi-level network security domain's malicious data traffic protection performance is better than former one. In this paper, we use a trust evaluation metric for measuring the security domain's performance and suggested algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.3
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• pp.391-400
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• 1994

Recently, the development of ATM switch, a backbone system of BISDN, is receiving worldwide study. Because the development of large communication equipments like a switching system need a lot of time and cost, the performance evaluation by menas of simulation is needed for the higher efficiency of development before actual implementation. So, a general and objective input environment is necessary for proper simulation. The main purpose of this paper is to offer a traffic generator which can provide such input environment as a file for computer simulation of ATM switch. To offer diverse input environment of ATM switch, we select parameters, and implement ATM traffic generator with software technology. Basides, a program to verify the propriety of ATM traffic generator in also proposed. It is expected that the proposed ATM traffic generator will offer diverse input environment for computer simulation to evaluate new ATM switching system, not influenced by any system structure.

• Journal of Korean Society of Transportation
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• v.33 no.5
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• pp.470-477
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• 2015

VMS informs the public of traffic and weather information in real time and functions to facilitate traffic flow. However, as smart phone navigation becomes more popular with the rapid propagation of the smart phone, the efficiency and applicability of VMS are challenged. Accordingly, this study aims to investigate the drivers' preference for the traffic information service between VMS and smart phone navigation by conducting a survey using a stated preference in Busan Metropolitan City in August 2013. This study found that 60% of survey respondents prefer VMS to the smart phone navigation. Further analysis to investigate the preference focused on the smart phone users revealed that female, younger, more educated, and less experienced drivers more rely on the smart phone navigation. Consequently, this study implicates that private and governmental institutes have to take a measure to develop the integrated traffic information system.