• Journal of the Korea Institute of Information Security & Cryptology
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• 제14권4호
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• pp.141-148
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• 2004

This paper proposes an IPSec accelerator performance analysis model based a queue model. It assumes Poison distribution as its input traffic load. The decoding delay is employed as a performance analysis measure. Simulation results based on the proposed model show around 15% differences with respect to actual measurements on field traffic for the BCM5820 accelerator device. The performance analysis model provides with reasonable hardware structure of network servers, and can be used to span design spaces statistically.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권9호
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• pp.4108-4122
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• 2016

To address challenges of an unprecedented growth in mobile data traffic, the ultra-dense network deployment is a cost efficient solution to off-load the traffic over other small cells. However, the real traffic is often much lower than the peak-hour traffic and certain small cells are superfluous, which will not only introduce extra energy consumption, but also impose extra interference onto the radio environment. In this paper, an elastic energy efficient cell management scheme is proposed based on flow scheduling among multi-layer ultra-dense cells by a SDN controller. A significant power saving was achieved by a cell-level energy manager. The scheme is elastic for energy saving, adaptive to the dynamic traffic distribution in the office or campus environment. In the end, the performance is evaluated and demonstrated. The results show substantial improvements over the conventional method in terms of the number of active BSs, the handover times, and the switches of BSs.

• Proceedings of the KSRS Conference
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.759-762
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• 2005

Recently, Intelligent Transportation System(ITS) has been applied to satisfy increasing traffic demand every year and to solve many traffic problems. Especially, Advanced Traveller Information System(ATIS) is a transportation system to optimize the trip of each other vehicle. It is important to provide the driver with quick and comfortable path from source to destination. However, it is difficult to provide a shortest path in a road network with dynamic cost. Because the existing research has a static cost. Therefore, in this paper we propose an operator for searching traffic dependent shortest path. The proposed operator finds the shortest path from source to destination using a current time cost and a difference cost of past time cost. Such a method can be applied to the road status with time. Also, we can expect a predicted arrival time as well as the shortest path from source to destination. It can be applied to efficiently application service as ITS and have the advantages of using the road efficiently, reducing the distribution cost, preparing an emergency quickly, reducing the trip time, and reducing an environmental pollution owing to the saving the fuel.

• Journal of the Korean Society of Safety
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• 제31권5호
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• pp.158-170
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• 2016

It has been applied several ways in order to prevent traffic accidents and speed management on the road which is one of very important factors to prevent accidents. In this study, it is analyzed whether the facility such as the flashing and crosswalk, speed cameras and intermittent warning signs affect on a driving deceleration or not. It has been shown that the flashing and crosswalk and speed cameras except intermittent warning signs play a role of reducing the driving speed. The result showed that these traffic safety facilities help to improve the average speed as well as velocity distribution which was derived by the speed deviation even if there were the difference between facilities. Speed limit display does not affect the deceleration of the driver. Therefore, it was founded in this research that there were the driving speed reduction effect due to the facilities on the road. In order to control the driving speed on the road, it is necessary to install facilities with appropriate location and spacing on the road. In addition, place that turns out suppressed speeding through speed management also are required adequate facilities such as speed cameras.

• Journal of Communications and Networks
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• 제18권5호
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• pp.818-825
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• 2016

Network management and anomaly detection are challenges in high-speed networks due to the high volume of packets that has to be analysed. Flow-based analysis is a scalable method which reduces the high volume of network traffic by dividing it into flows. As sampling methods are extensively used in flow generators such as NetFlow, the impact of sampling on the performance of flow-based analysis needs to be investigated. Monitoring using sampled traffic is a well-studied research area, however, the impact of sampling on flow-based anomaly detection is a poorly researched area. This paper investigates flow sampling methods and shows that these methods have negative impact on flow-based anomaly detection. Therefore, we propose an efficient probabilistic flow sampling method that can preserve flow traffic distribution. The proposed sampling method takes into account two flow features: Destination IP address and octet. The destination IP addresses are sampled based on the number of received bytes. Our method provides efficient sampled traffic which has the required traffic features for both flow-based anomaly detection and monitoring. The proposed sampling method is evaluated using a number of generated flow-based datasets. The results show improvement in preserved malicious flows.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제19권10호
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• pp.1075-1082
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• 2009

Using GIS data of C-si as basic data when making noise map of road traffic, we estimated exactly the noise excess areas and consequently suggested the population and the area exposed to road traffic noise accurately. We made 3D noise map to assess regional distribution of noise quantitatively. The noise map consists of noise prediction model based on data base such as traffic volume and speed changes for estimating quantitatively the noise and 3D urban space model which includes locations of noise sources, 3D buildings, topography and roads. We made noise standard map according to land use conditions and compared this map to road traffic noise map, and consequently made excess noise map. Using excess noise map, we assessed areas which exceed environmental noise level standards and noise guidelines quantitatively and effectively through GIS spatial analysis, and consequently more accurate noise exposed area and noise exposed population could be estimated. To show buildings' outer walls noise exposure, we analyzed 3D urban noise distributions using 3D-analysis of GIS.

• Journal of Environmental Impact Assessment
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• 제16권6호
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• pp.485-494
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• 2007

Air pollution and traffic noise from roads distributed near residential area has been a major social problem. In this study, an environmental pollution map for a residential area of Shihung-city was made by an expectation model based on hourly traffic volume change. Using the result from the model, a plan to reduce population in the residential area was established. The result of the modelling is summarized as follows: 1. At peak traffic hours (18 o'clock), 301-500 degree in hazardous and $d_{25}$ degree (25% of the residents are suffering extremely from the noise) in noise pollution were predicted in Jeongwang Main Road in Shihung city. 2. The calculated critical pollutant standard index, PSI showed the air pollution level, especially PM-10 high enough to require re-entrainment. 3. It was expected air pollution would extensively extend over the area distribution of each degree. However, noise pollution problem was limited to the area near roads.

• The Korean Journal of Air & Space Law and Policy
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• 제18권
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• pp.105-134
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• 2003

This paper describes generic cognitive aspects of the air traffic controller's performance and perceptive activities unveiled through the past literature study. which underlines mental modelling and mental picture presented in the middle of complicated situational awareness and decision making process when air traffic controller comes to determine the distance between aircraft under control to maintain air traffic in a safe, orderly and expeditious way. It also describes human limit in terms of human memory in conjunction with relative workloads and environmental factor. In conclusion, It suggest that ATC authority will take into account the qualitatiive adjustment of training requirement necessary for ATC facility rating and refresher training to allow them more preparedness for better situational awareness and optimal decision making. In this paper controller's behavioral activators affecting their job performance are addressed in perspective of aviation safety.

• Journal of Environmental Impact Assessment
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• 제21권4호
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• pp.567-572
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• 2012

This paper suggests the set-up plan of the assessment scope in road noise considering road characteristics with the prediction model of road noise. The RLS90 prediction model with some assumptions is used to establish the assessment scope of road noise. The main contents of the applied assumptions are smooth drive of cars, flat region, location of all noise sources in one lane, drive in design speed, and set-up of assessment scope according to traffic volume and car speed. The information of traffic volume to predict road noise is obtained by the distribution of small cars and full-sized cars in road. In this study, the total traffic volume in road is computed by adding the number of small cars to the conversion number of small cars, which means the number of small cars making the same noise as one full-sized car. The prediction result of road noise with the influence factor of traffic volume, car speed, distance between road and receiver is presented. The resultant assessment scope of road noise is obtained by combining road noise prediction data with the set-up standard of road noise assessment scope.

• Journal of Korea Society of Digital Industry and Information Management
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• 제5권4호
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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.