• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.6
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• pp.63-73
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• 2011

Travel speed is an important parameter for measuring road traffic. UTIS(Urban Traffic Information System) was developed as a mobile detector for measuring link travel speeds in South Korea. After investigation, we founded that UTIS includes some missing data caused by the lack of probe vehicles on road segments, system failures and etc. Imputation is the practice of filling in missing data with estimated values. In this paper, we suggests a new model for imputing missing data to provide accurate link travel speeds to the public. In the field test, new model showed the travel speed measuring accuracy of 93.6%. Therefore, it can be concluded that the proposed model significantly improves travel speed measuring accuracy.

• Journal of Navigation and Port Research
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• v.37 no.5
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• pp.447-452
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• 2013

Vessel traffic system uses multiple sea surveillance radars as a primary sensor to obtain maritime traffic information like as ship's position, speed, course. The systematic errors such as the range bias and the azimuth bias of the two-dimensional radar system can significantly degrade the accuracy of the radar image and target tracking information. Therefore, the systematic errors of the radar system should be corrected precisely in order to provide the accurate target information in the vessel traffic system. In this paper, it is proposed that the method compensates the range bias and the azimuth bias using AtoN information installed at VTS coverage. The radar measurement residual error model is derived from the standard error model of two-dimensional radar measurements and the position information of AtoN, and then the linear Kalman filter is designed for estimation of the systematic errors of the radar system. The proposed method is validated via Monte-Carlo runs. Also, the convergence characteristics of the designed filter and the accuracy of the systematic error estimates according to the number of AtoN information are analyzed.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1722-1730
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• 2007

According to the result of recent studies, it was revealed that the error of safety-related personnel still plays a significant role in the accidents and/or incidents of a railway system. Accordingly, in order to reduce as well as prevent human errors, it is necessary to: (1) identify the root cause of accidents/incidents, and (2) conduct a research that can provide a systematic as well as an effective way to deal with the identified human errors. To this end, it is essential to suggest appropriate countermeasures based on the result of a task load analysis, which can soundly reduce a high level of the task load put on safety-related personnel. In the light of this concern, about the tasks of railway traffic signallers, a detailed task analysis was conducted in this study. After that, the associated task load scores were quantified by NASA-TLX technique that is one of the most well-known subjective workload measurement techniques. As a result, a set of significant tasks that could put a high task load on railway traffic signallers was identified.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.8
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• pp.335-342
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• 2013

Nowadays, the traffic type and behavior are extremely diverse due to the growth of network speed and the appearance of various services on Internet. For efficient network operation and management, the importance of application-level traffic identification is more and more increasing in the area of traffic analysis. In recent years traffic identification methodology using statistical features of traffic flow has been broadly studied. However, there are several problems to be considered in the identification methodology base on statistical features of flow to improve the analysis accuracy. In this paper, we recognize these problems by analyzing the ground-truth traffic and propose the solution of these problems. The four problems considered in this paper are the distance measurement of features, the selection of the representative value of features, the abnormal behavior of TCP sessions, and the weight assignment to the feature. The proposed solutions were verified by showing the performance improvement through experiments in campus network.

• Journal of Korea Society of Digital Industry and Information Management
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• v.20 no.1
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• pp.109-118
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• 2024

Recently, a social issue has arisen involving RDDoS attacks following the sending of threatening emails to security administrators of companies and institutions. According to a report published by the Korea Internet & Security Agency and the Ministry of Science and ICT, survey results indicate that DDoS attacks are increasing. However, the top response in the survey highlighted the difficulty in countering DDoS attacks due to issues related to security personnel and costs. In responding to DDoS attacks, administrators typically detect anomalies through traffic monitoring, utilizing security equipment and programs to identify and block attacks. They also respond by employing DDoS mitigation solutions offered by external security firms. However, a challenge arises from the initial failure in early response to DDoS attacks, leading to frequent use of detection and mitigation measures. This issue, compounded by increased costs, poses a problem in effectively countering DDoS attacks. In this paper, we propose a system that creates detection rules, periodically collects traffic using mail detection and IDS, notifies administrators when rules match, and Based on predefined threshold, we use IPS to block traffic or DDoS mitigation. In the absence of DDoS mitigation, the system sends urgent notifications to administrators and suggests that you apply for and use of a cyber shelter or DDoS mitigation. Based on this, the implementation showed that network traffic was reduced from 400 Mbps to 100 Mbps, enabling DDoS response. Additionally, due to the time and expense involved in modifying detection and blocking rules, it is anticipated that future research could address cost-saving through reduced usage of DDoS mitigation by utilizing artificial intelligence for rule creation and modification, or by generating rules in new ways.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.77-87
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• 2018

Traffic Density is the most important of the three primary macroscopic traffic stream parameters, because it is most directly related to traffic demand(Traffic Engineering, 2004). It is defined as the number of existing vehicles within a given distance at a certain time. However, due to weather, road conditions, and cost issues, collecting density directly on the field is difficult. This makes studies of density less actively than those of traffic volume or velocity. For these reasons, there is insufficient attempts on divers collecting methods or researches on the accuracy of measured values. In this paper, we used the 'Density Measuring System' based on the synthesise technology of several camera images as a method to measure density. The collected density value by the 'Density Mesuring System' is selected as the true value based on the density define, and this value was compared with the density calculated by the traditional measurement methods. As a result of the comparison, the density value using the fundamental equation method is the closest to the true value as RMSE shows 1.8 to 2.5. In addition, we investigated some issues that can be overlooked easily such as the collecting interval to be considered on collecting density directly by calculating the moment density and the average density. Despite the actual traffic situation of the experiment site is LOS B, it is difficult to judge the real traffic situation because the moment density values per second are observed max 16.0 (veh/km) to min 2.0 (veh/km). However, the average density measured for 15 minutes at 30-second intervals was 8.3-7.9 (veh/km) and it indicates precisely LOS B.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.528-533
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• 2000

This paper is concerned to remote monitoring It management system on the bring up house of agricultural, lomestic animal, aquatic products. That is necessary for traffic network and monitoring unit for transmission the environment data of temperature, humidity and electric etc.. This study is executed the experimental research for structure of system. which are composed sensing interface, multi-processing, traffic network and algorithm. Result, that is respected the effective management, increase of produce and prevent of calamity on the bring up house by low cost of set & remain.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.1969-1980
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• 2013

The Traffic congestion is caused by the increasing traffic demand. Thus, economic losses have been increasing every year. To solve these problems, car sharing and rental car systems that are equipped with IT technologies emerge. Car sharing has many advantages-the alleviation of the traffic congestion, the saving of maintenance cost for cars, the reduction of car possessiveness, the solution for the hassle of car ownership, for business and personal duty, and the improvement of connectivity between public transportations-. The goal of the car sharing is to achieve low-carbon and eco-friendly transportation. In this study, we review papers related to the car sharing system and the cost system of traffic systems. We estimate the optimal cost of the cloud traffic system that is one of the car sharing services. We suggest a methodology to estimate operational cost and use cost through the analysis of cost system between similar traffic means. The range of the maximum and minimum cost was determined through the comparison and analysis of similar traffic means. Expected demand and the cost that people are willing to pay were estimated through optimized value pricing. The minimum cost per hour that was compared to the cost of rental car was estimated at 5,333 won and the maximum cost per hour that was compared to taxi cost was estimated at 17,700 won. The cost for users was estimated at 6,930 won. The cost of 50% demands was estimated at 6,550won. Future studies should analyze service hours of users, weather, demand pattern and trend and consider them into the cost estimation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.74-80
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• 2021

When a berth is built close to a fairway, a moored vessel will be affected by the ship waves generated by navigating vessels. In this study, a portable measurement system was developed to measure the roll motion of an actual vessel, and the results were compared with simulation results. The simulation results showed that the roll motion satisfies the loading safety criteria. However, the actual results of the vessel, did not satisfy the criteria in some cases. In this study, 18 cases that did not satisfy the loading safety criteria were analyzed. Among these cases, three cases were affected by a different time zone of the remaining 15 cases, 11 cases (73.3%) were observed to be consistent with arrival times of passenger ships of more than 10,000GT sailing between in Mokpo and Jeju. The results of this study can be used to reflect marine traffic characteristics in the assessment of loading safety, which can increase the reliability of results of the loading safety assessment of ships.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.1
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• pp.37-43
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• 2018

There has been the migration to a performance-based approach in many areas which include transition planning at global, regional and local levels, performance-based navigation and safety management. Achieving continuous success of Air Traffic Management (ATM) systems would require a performance-based approach to raise productivity and efficiency of it through performance measurements and reviews. This paper considers establishment planning of performance measurement and evaluation system for ATM. Related to key performance areas proposed by International Civil Aviation Organization, performance indicators and metrics which could be used to measure and evaluate ATM performance are presented. Also, organizational system and operational planning for efficient operation of ATM are presented.