• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.1
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• pp.17-32
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• 1996

In this paper, a model for two-layered video traffic is proposed. The performance analysis of the proposed model and the effects of two-layer coding scehemes in ATM networks are also studied. ATM-based networks give the possibility to support image codingat variable bit rate(VBR). Two layer coding is one of the very promising methods among many proposed methods to compensate the cell loss, the major drawback in ATM networks. From the experimental data of the 2-layer coded video traffics, it is observed that traffic patterns of base layer and enhanced layer are highly correlate to each other, when constant image quality is kept. With this observation, coded two layered video traffic can be modeled as 2-dimensional Markov chain. The model well fit the real experimental data. The model was used for the analysis of the performance of statistical multiplexer with priorites in ATM networks.

• Interaction and multiscale mechanics
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• v.3 no.4
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• pp.373-387
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• 2010

This study is intended to assess low frequency sound radiated from a viaduct under normal traffic. The bridge comprises steel box girders and wide cantilever decks on which vehicles pass. The low frequency sound and the acceleration response of the bridge under normal traffic are measured to investigate how bridge vibrations affect the low frequency sound observed near the bridge. Observations demonstrate that strong relationships exist between frequency characteristic of bridge's acceleration response and the sound pressure level of low frequency sound. A noteworthy point is that the dynamic feature of the sound pressure level is mostly affected by dynamic feature of the span locating near the observation point.

• Journal of Digital Contents Society
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• v.5 no.2
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• pp.151-156
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• 2004

This paper presents process model to accomplish traffic engineering in Internet. The process model consists of 4 stages. The first stage is the formulation of a control policy dominated network operation. The second stage is the observation of the network state through a set or monitoring functions. The third stage is the characterization or traffic and analysis or the network state. The final stage is the optimization of network performance. the four stages of the process model defined above are iterated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.253-258
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• 2015

The purpose of this study is to find suitable probability distribution function of complex distribution data like multimodal. Normal distribution is broadly used to assume probability distribution function. However, complex distribution data like multimodal are very hard to be estimated by using normal distribution function only, and there might be errors when other distribution functions including normal distribution function are used. In this study, we experimented to find fit probability distribution function in multimodal area, by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. By using chi-squared statistic, gaussian mixture model(GMM) is the fittest model rather than other distribution functions, such as extreme value, generalized extreme value, logistic, and normal distribution. GMM was found to the fit model regard to multimodal data of maritime traffic flow distribution. Probability density function for collision probability and traffic flow distribution will be calculated much precisely in the future.

• Spatial Information Research
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• v.22 no.1
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• pp.9-17
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• 2014

This study was intended to reliably predict the traffic green house gas emission in Daegu with the use of spatial statistical technique and calculate the traffic green house gas emission of each administrative district on the basis of the accurately predicted emission. First, with the use of the traffic actually surveyed at a traffic observation point, and traffic green house gas emission was calculated. Secondly, on the basis of the calculation, and with the use of Universal Kriging technique, this researcher set a suitable variogram modeling to accurately and reliably predict the green house gas emission at non-observation point suitable through spatial correlation, and then performed cross validation to prove the validity of the proper variogram modeling and Kriging technique. Thirdly, with the use of the validated kriging technique, traffic green gas emission was visualized, and its distribution features were analyzed to predict and calculate the traffic green house gas emission of each administrative district. As a result, regarding the traffic green house gas emission of each administration, it was found that Bukgu had the highest green house gas emission of $291,878,020kgCO_2eq/yr$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.233-236
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• 2010

This paper describes the packet traffic management of the Ubiquitous Healthcare System. In this system, ECG signal and accelerometer signal is transmitted from a wearable health shirt (WHS) to the base station. However, with the increment of users in this system, traffic over-load issue occurs. The main aim of this paper is to reduce the traffic over-load issue between sensor nodes by only transmitting the required signals to the base station when irregular activities are observed. In order to achieve this, in-network processing is adapted where the process of observation is conducted inside the sensor node of WHS. Results shows that irregular activities such as fall can be detected on real-time inside the sensor node and thus resolves traffic over-load issue.

• IEMEK Journal of Embedded Systems and Applications
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• v.18 no.3
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• pp.125-132
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• 2023

Roundabouts have strengths in traffic flow and safety but can present difficulties for inexperienced drivers. Demand to acquire and analyze drone images has increased to enhance a traffic environment allowing drivers to deal with roundabouts easily. In this paper, we propose a roundabout traffic analysis system that detects, tracks, and analyzes vehicles using a deep learning-based object detection model (YOLOv7) in drone images. About 3600 images for object detection model learning and testing were extracted and labeled from 1 hour of drone video. Through training diverse conditions and evaluating the performance of object detection models, we achieved an average precision (AP) of up to 97.2%. In addition, we utilized SORT (Simple Online and Realtime Tracking) and OC-SORT (Observation-Centric SORT), a real-time object tracking algorithm, which resulted in an average MOTA (Multiple Object Tracking Accuracy) of up to 89.2%. By implementing a method for measuring roundabout entry speed, we achieved an accuracy of 94.5%.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.2
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• pp.111-116
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• 2021

Normal Operation Safety Survey (NOSS) is a safety management tool used by air traffic control organizations to measure data related to threats and errors to proactively prevent accidents before they occur. NOSS was developed to be applied to the air traffic control field according to the concept of Line Operation Safety Audit (LOSA) conducted by airlines to reduce human errors in the cockpits. Safety management based on data is crucial for the prevention of control-related accidents, and the competency of observers for this is important for the successful implementation of NOSS. Based on LOSA implementation experiences and expert interviews, this paper introduces the international NOSS methods and discusses the key factors required for effective observation and the implementation methods and implications of NOSS observer training.

• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.421-431
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• 2022

The purpose of this research is to determine the point of fixation of the driver during the process of driving. Based on the results of this research, the driving instructor can make a judgement on what the trainee stare on the most. Traffic accidents have become a serious concern in modern society. Especially, the traffic accidents among unskilled and elderly drivers are at issue. A driver should put attention on the vehicles around, traffic signs, passersby, passengers, road situation and its dashboard. An eye-tracking-based application was developed to analyze the driver's gaze behavior. It is a prototype for real-time eye tracking for monitoring the point of interest of drivers in driving practice. In this study, the driver's attention was measured by capturing the movement of the eyes in real road driving conditions using these tools. As a result, dwelling duration time, entry time and the average of fixation of the eye gaze are leading parameters that could help us prove the idea of this study.

• Journal of the Korean Society of Safety
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• v.32 no.3
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• pp.74-82
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• 2017

This study was conducted to test the impacts of distractions caused by smartphones on pedestrians whilst walking alongside or across vehicular traffic in a high-density urban zone in South Korea. Through this study, we propose objective evidence for a link between the risk of traffic accidents and distractions from smartphones for pedestrians because of less likely notice activities surrounding road along their walking. This means that smartphones usage may cause inattentional blindness even during a simple activity that should require few cognitive resources. We conducted an experiment comparing pedestrian behavioral patterns of walking with smartphone distractions (such as listening to music with earphones or sending text messages) and normal walking without any distractions. In the experiment, participants walked along a pedestrian path prescribed by researchers and were observed at 8 points which were as follows: two observation points through which participants were instructed to listen to music whilst walking, two points where participants were instructed to send text messages, and four points through which participants were instructed not to use a smartphone at all. According to pedestrian behavior analysis, there is a trend for attention to be distributed amongst whatever other activities pedestrians are doing whilst walking. Therefore, this study proposes that pedestrians walking with such distractions are at a higher risk of traffic accidents compared to those who walk without such distractions. Thus, we advise for the South Korean government to consider ways to traffic policy that will enhance traffic safety for pedestrians.