• Journal of Communications and Networks
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• 제3권4호
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• pp.324-333
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• 2001

The Differentiated Services (Diffserv) framework has been proposed by the IETF as a simple service structure that can provide different Quality of Service (QoS) to different classes of packets in IP networks. IP packets are classified into one of a limited number of service classes, and are marked in the packet header for easy classification and differentiated treatments when transferred within a Diffserv domain. The Diffserv framework defines simple and efficient QoS differentiation mechanisms for the Internet. However, the original Diffserv concept does not provide a complete QoS management framework. Since traffic flows in IP networks are unidirectional from one network point to the other and routing paths and traffic demand get dynamically altered, it is important to monitor end-to-end traffic status, as well as traffic status in a single node. This paper suggests a distributed QoS monitoring method that collects the statistical data of each service class in every Diffserv router and calculates edge-to-edge QoS of the aggregated IP flows by combining routing topology and traffic status. A format modeling of edge-to-edge Diffserv flows and algorithms for aggregating edge-to-edge QoS is presented. Also an SNMP-based QoS management prototype system for Diffserv networks is presented, which validates our QoS management framework and demonstrates useful service management functionality.

• 한국환경과학회지
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• 제21권9호
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• pp.1149-1162
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• 2012

The impact of a considerable increase in traffic volume on the emission and concentrations of air pollutants was investigated at three beaches (Haeundae (HB), Gwanganri (GB), and Songjeong (SB)) in Busan during beach opening period (BOP) in 2011. During the BOP, passenger car was the major vehicle type, followed by taxi, and van. CO was the major contributor of total air pollutant emissions followed by NOx, VOC, and $PM_{10}$. For the temporal variation of the emission of air pollutants during the BOP, it was generally the highest in the afternoon followed by the evening and morning, except for SB. For the spatial variation of their emission, it was the highest at GB followed by SB and HB. The emissions of air pollutants during the BOP were generally higher than those during the Non-BOP, except for HB. In contrast, the significant impact of the traffic volume increase on the concentrations of air pollutants at monitoring sites near the three beaches during the BOP were not found compared to the Non-BOP due to the significant distances between monitoring sites of air pollutants and monitoring sites of traffic volume at the beaches.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 춘계학술대회
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• pp.449-450
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• 2015

이 논문에서는 XG-PON (10-Gbps-capable passive optical network) 시스템에서 전송요청을 사용하지 않는 동적대역할당 알고리즘의 성능을 평가한다. OLT (optical line termination)는 ONU(optical network unit)의 상향 대역폭 사용량을 monitoring 해서 ONU의 전송허가량을 추측한다.

• 대한인간공학회지
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• 제29권1호
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• pp.17-24
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• 2010

There has been recent interest in intelligent vehicle technologies, such as advanced driver assistance systems (ADASs) or in-vehicle information systems (IVISs) that offer a significant enhancement of safety and convenience to drivers and passengers. However, unsuitable design of HMI (Human Machine Interface) must increase driver distraction and workload, which in turn increase the chance of traffic accidents. Distraction in particular often occurs under a heavy driving workload due to multitasking with various electronic devices like a cell phone or a navigation system while driving. According to the 2005 road traffic accidents in Korea report published by the ROad Traffic Authority (ROTA), more than 60% of the traffic accidents are related to driver error caused by distraction. This paper suggests the structure of vehicle environment for real-time driving behavior monitoring system while driving which is can be used the driver workload management systems (DWMS). On-road experiment results showed the feasibility of the suggested vehicle environment for driving behavior monitoring system.

• 한국환경과학회지
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• 제15권8호
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• pp.737-744
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• 2006

Present study was designed to characterize the concentrations of major roadside air pollutants in Daegu and to compare with those of Seoul and Busan. Evaluated were the exceedance frequence of mean concentrations of target compounds(CO, NO$_2$, O$_3$, PM$_{10}$, SO$_2$) and the relationship for time variation. Two air pollution monitoring stations(one roadside station and one residential station) in Daegu were selected for this study. In addition, one roadside monitoring station from each of Seoul and Busan was chosen for the comparison of Daegu monitoring stations. The data analyzed in the current study were collected from 1998 to 2000 by Daegu Regional Environmental Management Office. The roadside concentrations of NO2 and PM to and the exceedance frequency of ambient air standard levels in Daegu were higher than those of Seoul and Busan. Except 03, the roadside concentrations of all target compounds showed following three distinguished patterns; first, possibly due to increased traffic density, the concentrations increased from 0500 to 0900(LST), second, the concentrations decreased from 0900 to 1700(LST) possibly due to the increased wind velocity and decreased traffic density, and finally, increased traffic density, the concentrations increased again from 1700 to 2100(LST). An implication was that major air pollution sources shifted from residential area to road-area during rush hours.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2483-2503
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• 2016

Traffic congestion is a severe problem in many modern cities around the world. Real-time and accurate traffic congestion identification can provide the advanced traffic management systems with a reliable basis to take measurements. The most used data sources for traffic congestion are loop detector, GPS data, and video surveillance. Video based traffic monitoring systems have gained much attention due to their enormous advantages, such as low cost, flexibility to redesign the system and providing a rich information source for human understanding. In general, most existing video based systems for monitoring road traffic rely on stationary cameras and multiple vehicle tracking method. However, most commonly used multiple vehicle tracking methods are lack of effective track initiation schemes. Based on the motion of the vehicle usually obeys constant velocity model, a novel vehicle recognition method is proposed. The state of recognized vehicle is sent to the GM-PHD filter as birth target. In this way, we relieve the insensitive of GM-PHD filter for new entering vehicle. Combining with the advanced vehicle detection and data association techniques, this multiple vehicle tracking method is used to identify traffic congestion. It can be implemented in real-time with high accuracy and robustness. The advantages of our proposed method are validated on four real traffic data.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.481-484
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• 2008

The research was carried out to suggest the bridge health monitoring systems that have been composed damage detection algorithm and a system for evaluation load carrying capacity of bridge by traffic loads for the purpose of safety management of bridge structure in efficient and economic.

• 대한전자공학회논문지TC
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• 제45권8호
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• pp.106-113
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• 2008

본 논문에서는 ntop, ethereal, netperf, nettest 등 기존의 네트워크 모니터링 시스템의 취약점을 보안하고 동적인 firewall 기능을 가진 네트워크 트래픽 매니지먼트 시스템인 MAGI를 설계, 구현하고 이를 분석한다. MAGI 는 소프트웨어로 개발된 기존의 네트워크 모니터링 시스템과는 달리 소프트웨어와 하드웨어가 결합된 형태를 가진다. 소프트웨어 측면에서는 기존 모니터링 시스템과 차별화된 웹 유저 인터페이스(web user Interface) 시스템을 적용하여 트래픽 분석 및 방화벽 적용이 간편할 뿐만 아니라, 하드웨어의 상태를 모니터링 및 관리 할 수 있는 기능을 지닌다. 웹 유저 인터페이스는 PHP 와 MySQL 을 연동하여 데이터베이스(database)를 이용할 수 있어 데이터 분석이 간편한 장점을 지닌다. 하드웨어 파트인 어플라이언스(appliance)는 네트워크에 브릿지(bridge) 모드로 설치하여 모니터링 하는 시스템에 부하가 걸리지 않게 구현하였다. 또한, 어플라이언스 관리를 위하여 ncurses 기반의 인터페이스를 만들어 탑재함으로써 다양한 환경에 적용이 가능하다.

• 대한교통학회지
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• 제27권5호
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• pp.29-37
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• 2009

대기환경의 중요성에 대한 인식이 커지면서, 교통관리 전략 수립에 대기질 개선여부를 반영시키고자 하는 많은 노력이 진행되고 있다. 그러나, 자료수집의 어려움 등으로 인해서 교통량과 대기질의 관계를 실증적으로 파악하고자 하는 연구는 많이 찾아볼 수 없는 상황이다. 이에, 본 연구에서는 서울시에서 구축해온 2005년~2007년 3년간의 대기 및 교통 모니터링 자료들을 활용하여 그 상관성을 살펴보았다. 이를 위해 두 모니터링 시스템간의 이격거리가 반경 1km이내의 지점만을 선별하고 그룹화하여 분석을 실시하였다. 분석대상 오염물질로는 CO, NO, $NO_2$, $PM_{10}$을 그 대상으로 하였으며, 분석결과 현재 구축된 두 자료의 상관성이 전반적으로 낮은 것으로 나타났다. 그러나, 타 오염물질에 비해 $NO_2$는 상대적으로 교통량과 높은 상관관계를 보였으며, 오전시간대, 강수 다음날의 자료를 사용한 경우 그 상관성이 높아지는 것을 확인하였다.

• Smart Structures and Systems
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• 제17권6호
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• pp.995-1015
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• 2016

In the design and condition assessment of bridges, it is usually necessary to take into consideration the extreme conditions which are not expected to occur within a short time period and thus require an extrapolation from observations of limited duration. Long-term structural health monitoring (SHM) provides a rich database to evaluate the extreme conditions. This paper focuses on the extrapolation of extreme traffic load effects on bridges using long-term monitoring data of structural strain. The suspension Tsing Ma Bridge (TMB), which carries both highway and railway traffic and is instrumented with a long-term SHM system, is taken as a testbed for the present study. Two popular extreme value extrapolation methods: the block maxima approach and the peaks-over-threshold approach, are employed to extrapolate the extreme stresses induced by highway traffic and railway traffic, respectively. Characteristic values of the extreme stresses with a return period of 120 years (the design life of the bridge) obtained by the two methods are compared. It is found that the extrapolated extreme stresses are robust to the extrapolation technique. It may owe to the richness and good quality of the long-term strain data acquired. These characteristic extremes are also compared with the design values and found to be much smaller than the design values, indicating conservative design values of traffic loading and a safe traffic-loading condition of the bridge. The results of this study can be used as a reference for the design and condition assessment of similar bridges carrying heavy traffic, analogous to the TMB.