• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.522-524
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• 2016

E-Navigation is required port operation for effective and safety. Maritime traffic data must be exchanged between Vessel Traffic Service Center and ship for e-navigation build. In this paper, We designed Open API system for the exchange and use of maritime traffic data. This system provide Open API data to $3^{rd}$ party.

• Convergence Security Journal
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• v.6 no.1
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• pp.55-63
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• 2006

In this paper, an algorithm that provisions absolute differentiation of packet delays is proposed with an objective for enhancing quality of service (QoS) in future packet networks. It features an adaptive scheme that compensates the deviation for prediction on the traffic to be arrived continuously. It predicts the traffic to be arrived at the beginning of a time slot and measures the actual arrived traffic at the end of the time slot, and derives the deviation between the two quantity. The deviation is utilized to the delay control operation for the next time slot to offset it. As it compensates the prediction error continuously, it shows superior adaptability to the bursty traffic as well as the constant rate traffic. It is demonstrated through simulation that the algorithm meets the quantitative delay bounds and shows superiority to the traffic fluctuation in comparison with the conventional mechanism.

• Journal of the Korea Society for Simulation
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• v.19 no.2
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• pp.137-145
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• 2010

This study presents an RTS(Real-time Traffic System) based on an LBS(Location Based Service) using 5.8~5.9GHz RSU(Road Side Unit). The proposed LBI(Location based Broadcast system on ITS) is a local information-based service supported by RSU for drivers, which has a feature of convergence between T-DMB system and ITS-based RTS. The convergence of local broadcasting station and ITS is realized by two-way communication and supports LBS(Location Based Service) by identifying of vehicle's location using RSU. Real-time information delivery and various services could be provided by information exchanges between LMM and local broadcasting stations. Furthermore, conventional technical limitations have been solved mutually such as transmission area limitation in RTS and one-way communication problem in T-DMB. This support real-time two-way communication to each driver. Therefore, it can be expected that traffic dispersion effects and services expansion for drivers by RTS and LBI. Finally, it is proposed to built and implement test-bed around institute.

• Convergence Security Journal
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• v.10 no.3
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• pp.69-75
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• 2010

At present, deterioration in service quality, which caused by increased network traffic from a lot of users in the same network, makes smooth communication service difficult. In this paper, we present policy-based QoS management system for VoIP service in order to supply smooth VoIP service to users. The presented system can guarantee quality of VoIP service even in huge traffic situation, and makes it possible to operate whole network in an efficient manner.

• ETRI Journal
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• v.30 no.2
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• pp.227-237
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• 2008

In this paper, an algorithm that provides absolute and proportional differentiation of packet delays is proposed with the objective of enhancing quality of service in future packet networks. It features an adaptive scheme that adjusts the target delay for every time slot to compensate the deviation from the target delay, which is caused by prediction error on the traffic to arrive at the next time slot. It predicts the traffic to arrive at the beginning of a time slot and measures the actual arrived traffic at the end of the time slot. The difference between them is utilized by the delay control operation for the next time slot to offset it. Because the proposed algorithm compensates the prediction error continuously, it shows superior adaptability to bursty traffic and exponential traffic. Through simulations we demonstrate that the algorithm meets the quantitative delay bounds and is robust to traffic fluctuation in comparison with the conventional non-adaptive mechanism. The algorithm is implemented with VHDL on a Xilinx Spartan XC3S1500 FPGA, and the performance is verified under the test board based on the XPC860P CPU.

• Journal of information and communication convergence engineering
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• v.5 no.2
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• pp.171-176
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• 2007

To give a guarantee a consistently high level of quality and reliability of Telematics traffic service, traffic flow forecasting is very important issue. In this paper, we proposed an adaptable integrated prediction model to predict the traffic flow in the future. Our model combines two methods, short-term prediction model and long-term prediction model with different combining coefficients to reflect current traffic condition. Short-term model uses the Kalman filtering technique to predict the future traffic conditions. And long-term model processes accumulated speed patterns which means the analysis results for all past speeds of each road by classifying the same day and the same time interval. Combining two models makes it possible to predict future traffic flow with higher accuracy over a longer time range. Many experiments showed our algorithm gives a better precise prediction than only an accumulated speed pattern that is used commonly. The result can be applied to the car navigation to support a dynamic shortest path. In addition, it can give users the travel information to avoid the traffic congestion areas.

• ETRI Journal
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• v.37 no.6
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• pp.1242-1250
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• 2015

It is very important to provide a parameterized quality of service (QoS) using traffic specification (TSPEC), such as mean data rate, maximum burst size, and peak data rate, when packets from the application layer need to be transmitted with guaranteed services in a high-rate wireless personal area network (HR-WPAN). As medium resources are limited, the optimal medium time required for each device needs to be estimated to share the resources efficiently among devices. This paper proposes a variable-service interval-based resource allocation algorithm to efficiently make a reservation of medium resources based on a parameterized QoS. In other words, the proposed algorithm calculates the number of medium access slots (MASs) based on TSPEC, local resources, and local conditions and determines suitable locations for the MASs within a superframe to accommodate more devices. The simulation results show that the proposed algorithm can accommodate more devices and has greater than 10% resource allocation efficiency in an HR-WPAN compared to existing schemes.

• Convergence Security Journal
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• v.7 no.2
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• pp.17-25
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• 2007

In this paper, an algorithm that provisions proportional differentiation of packet delays is proposed with an objective for enhancing quality of service (QoS) in future packet networks. It features an adaptive scheme that adjusts the target delay every time slot to compensate the deviation from the target delay which is caused by the prediction error on the traffic to be arrived in the next time slot. It predicts the traffic to be arrived at the beginning of a time slot and measures the actual arrived traffic at the end of the time slot. The difference between them is utilized to the delay control operation for the next time slot to offset it. As it compensates the prediction error continuously, it shows superior adaptability to the bursty traffic as well as the exponential rate traffic. It is demonstrated through simulations that the algorithm meets the quantitative delay bounds and shows superiority to the traffic fluctuation in comparison with the conventional non-adaptive mechanism. The algorithm is implemented with VHDL on a Xilinx Spartan XC3S1500 FPGA and the performance is verified under the test board based on the XPC860P CPU.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.68-71
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• 2009

All-IP network requires change of the existing IP network engineering methods as the convergence service market between communication and broadcasting industries using IP network is growing rapidly. Especially the video services like IPTV require more strict transmission quality and higher bandwidth than the existing data services. So it is difficult to design All-IP network by the over-provisioning method which used to be used for the existing IP network design. It also requires a heavy investment which becomes one of big obstacles to the IPTV service expansion. In order to reduce the investment costs, it is required to design an optimized network by maximizing the utilization of the network resources and at the same time maintaining the customer satisfaction in terms of service quality. In this paper, we first analyze the effects of IPTV traffic on the existing internet. Then we compare two traffic engineering technologies, which are dimensioning without admission control and dimensioning with admission control, on the All-IP network design by simulation. Finally, we suggest cost effectiveness of traffic engineering technologies for designing the All-IP network.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.2
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• pp.60-64
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• 2006

In typical video streaming services such as MPEG encoded video, the transmission data sizes change depending on the frame types and the required bandwidth for QoS support also changes as time passes. Accordingly, in video streaming services using the Internet it could happen that the video services stop occasionally due to instantaneous deficiencies of the required bandwidth under unexpected congestion even if the highest priority is allocated to the service by network administration. In this paper, we investigate several methods for bandwidth allocation and traffic engineering to support MPEG video traffic and propose a new method to reduce the transmission delay and enhance the throughput, there by provisioning the QoS requirements. In the proposed scheme, LSPs are established based on temporal variation patterns of the Internet traffic and the CQ_LLQ policing scheme is applied for traffic shaping at the ingress routers. Finally we verified the performance of the proposed scheme via computer simulations using OPNET.