• 한국음향학회:학술대회논문집
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• 한국음향학회 2004년도 춘계학술발표대회 논문집 제23권 1호
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• pp.263-266
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• 2004

This paper describes an intelligent piezoelectric traffic sensor which can be detected the over-weighted vehicles In motion. Based on finite element analysis for the sensor, the sensitivity was analyzed and the design was optimized. Studied parameters are the material properties of constitutional parts, the geometry of the sensor, the weight of the vehicle, and the speed of the vehicle. To verify the simulated results, we manufactured the sensor having the optimized geometry and the sensitivity was measured in the range from 0.5 to 3 ton of tensile and compressive stress. The measured results shows that the sensitivity and linearity of the sensor are closely agree with the designed values.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 Asia Navigation Conference
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• pp.208-216
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• 2004

Since 2000, the authors have been developing remote radar network system to observe the vessel traffic in Tokyo Bay. In December 2002, the first operational remote radar station was set at the National Defense Academy in Yokosuka, and vessel traffic observation was started. However, it was impossible to perform accurate observation in the northern part of Tokyo Bay by this Yokosuka radar station only. In September 2003, the second remote radar station and AIS receiving station were installed at Higashi Ogishima in Kawasaki. This second radar enabled us to carry out accurate observation in that area. Both radars can be remotely controlled from the monitoring station in Tokyo University of Marine Science and Technology. On September 30 and October 1,2003, the vessel traffic observation was carried out using both radars. Combining radar images observed by both radars, the ships' tracks were taken and the dangerous ships were extracted by using SJ value and Bumper Model. The time changes of dangerous ship density in some areas in Tokyo Bay and utilization ratio of the traffic routes were also investigated. In addition, analyzing the AIS date received at Kawasaki station, the positions and speed vectors of the ships equipped with AIS were shown.

• Environmental Analysis Health and Toxicology
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• 제30권
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• pp.10.1-10.14
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• 2015

Recent cohort studies have relied on exposure prediction models to estimate individual-level air pollution concentrations because individual air pollution measurements are not available for cohort locations. For such prediction models, geographic variables related to pollution sources are important inputs. We demonstrated the computation process of geographic variables mostly recorded in 2010 at regulatory air pollution monitoring sites in South Korea. On the basis of previous studies, we finalized a list of 313 geographic variables related to air pollution sources in eight categories including traffic, demographic characteristics, land use, transportation facilities, physical geography, emissions, vegetation, and altitude. We then obtained data from different sources such as the Statistics Geographic Information Service and Korean Transport Database. After integrating all available data to a single database by matching coordinate systems and converting non-spatial data to spatial data, we computed geographic variables at 294 regulatory monitoring sites in South Korea. The data integration and variable computation were performed by using ArcGIS version 10.2 (ESRI Inc., Redlands, CA, USA). For traffic, we computed the distances to the nearest roads and the sums of road lengths within different sizes of circular buffers. In addition, we calculated the numbers of residents, households, housing buildings, companies, and employees within the buffers. The percentages of areas for different types of land use compared to total areas were calculated within the buffers. For transportation facilities and physical geography, we computed the distances to the closest public transportation depots and the boundary lines. The vegetation index and altitude were estimated at a given location by using satellite data. The summary statistics of geographic variables in Seoul across monitoring sites showed different patterns between urban background and urban roadside sites. This study provided practical knowledge on the computation process of geographic variables in South Korea, which will improve air pollution prediction models and contribute to subsequent health analyses.

• 정보보호학회논문지
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• 제22권6호
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• pp.1315-1324
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• 2012

보안 이벤트 시각화 기법은 기존의 시각화 기술을 네트워크 보안 분야에 적용한 형태로써 네트워크 보안과 관련있는 이벤트를 사용하여 네트워크의 트래픽 흐름과 보안 상황을 쉽고 빠르게 분석 및 탐지하는 기술이다. 특히 종단간의 연결 이벤트인 세션을 시각화하여 네트워크 이상 상황을 탐지하는 기술은 상대적으로 패킷 감시 기법에서 발생하는 오버헤드를 줄일 수 있고 알려지지 않은 공격 패턴들은 쉽게 탐지할 수 있어서 좋은 해결책이 되고 있다. 하지만, 서버들의 정상 활동과 네트워크 공격이 종단간의 유사한 연결 패턴을 가질 경우 세션 기반의 시각화 기법들은 공격 상황과 정상 상황을 구분하는 기능이 매우 취약하다. 따라서 본 논문에서는 세션 기반 시각화 기법에서 서버들의 정상 활동과 네트워크 공격 상황을 상세하게 구분할 수 있는 IP 주소 분할 표시 분석 방법 및 포트 특성 분석 방법을 제안하고자 한다. 제안하는 세션 기반의 공격 시각화 탐지 방법은 다른 공격 탐지 방법들과는 의존성이 없기 때문에 기존의 다양한 네트워크 공격 분석 및 탐지에 활용될 수 있고, 또한 네트워크 관리자에게는 현재 네트워크에서 발생되는 보안 위협을 보다 빠르게 판단할 수 있도록 도움을 준다.

• 한국정보통신학회논문지
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• 제24권8호
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• pp.963-969
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• 2020

지역 내의 도시들은 인구수, 계절, 교통량, 산업단지 등의 변수에 따라 대기오염의 수치가 다르게 관측되기 때문에 소규모 지역에 대해 정확하게 모니터링을 할 수 없는 문제점이 발생하고 있다. 이러한 문제점을 해결하기 위해 본 논문에서는 인체에 악영향을 미치는 대표적인 대기오염 물질 SO2, PM10, NO2, CO, O3이 관측되는 소규모 지역에 대해 결정계수(Coefficient of determination)를 통해 비교분석 하였다. 그리고 본페로니(Bonferroni) 다중 비교분석을 기반하여 기간별 대기 오염도를 나타내었다. 그리고 모니터링 시스템을 위해 지도를 각 소규모 도시의 좌표와 연동하여 분석 데이터를 기반으로 소규모 도시들에 대한 대기오염 물질을 시각화 하였다. 이를 통해 지역에 대한 대기오염 물질을 보다 정밀하게 사용자에게 모니터링 시스템을 제공할 수 있으며 일상생활에서 대기오염으로 발생할 수 있는 사고로부터 예방할 수 있을 것으로 보인다.

• Smart Structures and Systems
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• 제32권3호
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• pp.153-166
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• 2023

Health monitoring of civil infrastructures, in particular, old bridges that are still in service, has become more than necessary, given the risk that a possible degradation or failure of these infrastructures can induce on the safety of users in addition to the resulting commercial and economic impact. Bridge integrity assessment has attracted significant research efforts over the past forty years with the aim of developing new damage identification methods applicable to real structures. The bridge of Ouled Mimoun (Tlemcen, Algeria) is one of the oldest railway structure in the country. It was built in 1889. This bridge, which is too low with respect to the level of the road, has suffered multiple shocks from various machines that caused considerable damage to its central part. The present work aims to analyze the stability of this bridge by identifying damages and evaluating the damage rate in different parts of the structure on the basis of a finite element model. The applied method is based on an inverse analysis of the normal stress responses that were calculated from the corresponding recorded strains, during the passage of a real train, by means of a set of strain gauges placed on certain elements of the bridge. The results obtained from the inverse analysis made it possible to successfully locate areas that were really damaged and to estimate the damage rate. These results were also used to detect an excessive rigidity in certain elements due to the presence of plates, which were neglected in the numerical reference model. In the case of the continuous bridge monitoring, this developed method will be a very powerful tool as a smart health monitoring system, allowing engineers to take in time decisions in the event of bridge damage.

• 한국멀티미디어학회논문지
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• 제14권7호
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• pp.933-939
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• 2011

최근 집중호우에 따른 침수 및 산사태와 같은 자연재해로 인해 여러 곳에서 많은 피해가 발생하고 있다. 집중호우의 경우 도로 침수가 발생하면 교통 혼잡 및 고립으로 인한 피해는 심각할 수 있다. 이러한 재난이 확대되는 것을 예방하기 위하여 사전에 상습침수구역, 재해 위험지역 등의 현장 정보를 분석하여 예방을 위한 모니터링 시스템이 필요하며, 과거 자연재해 이력 데이터를 사용하여 자연재해 발생 당시의 교통량, 속도 등을 파악한다면 재해 규모, 강우량 등에 따른 교통 혼잡의 변화를 분석할 수 있다. 본 연구는 부산시 남구 대연동의 대남교차로를 시작으로 광안대교를 지나 올림픽 교차로까지 연구대상지역으로 설정하고 과거 이력 데이터를 사용하여 선택된 도로에서의 과거재해정보와 해당 날짜의 교통량 등의 정보를 검색할 수 있는 시스템을 구현하였다.

• 한국대기환경학회지
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• 제34권4호
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• pp.542-553
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• 2018

Since many previous studies reported the health effect of air pollution and indicated traffic as a major pollution source, significant policy efforts have been made to control traffic to reduce air pollution. However, there have been few studies that evaluated such policy implementation. In Seoul, Korea, the exclusive median bus lane system was implemented in 2004, and the metropolitan government applied air pollution reduction policies such as conversion of diesel buses to compressed natural gas buses and installation of emission control devices. This paper aimed to investigate the impact of the exclusive median bus lane system on air pollution reduction. Using hourly concentrations of particulate matter ($PM_{10}$) and nitrogen dioxide ($NO_2$) measured at 131 regulatory monitoring sites in Seoul and Gyeonggi-do for 2001-2014, we calculated annual and daily average concentrations at each site. We assessed the impact of the policy using differences-in-differences analysis by annual and daily average models after adjusting for geographic and/or meteorological variables. This method divides population into treatment and control groups with and without policy application, and compares the difference between the two time periods before and after the policy implementation in the treatment group with the difference in the control group. We classified all monitoring sites into treatment and control groups using two definitions: 1) Seoul vs. Gyeonggi-do; 2) within vs. outside 300 meters from the median bus lane. Pre- and post-policy periods were defined as 2001-2005 and 2006-2014, and 2004 and 2014 in the annual and daily models, respectively. The decrease in $PM_{10}$ concentrations between the two periods across monitoring sites in the treatment group was larger by $1.73-5.88{\mu}g/m^3$ than in the control group. $NO_2$ also showed the decrease without statistical significance. Our findings suggest that an efficient public transport policy combined with pollution abatement policies can contribute to reduction in air pollution.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권11호
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• pp.5654-5673
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• 2016

Participatory sensing applications rely on recruiting appropriate participants to share their surrounding conditions with others, and have been widely used in many areas like environmental monitoring, health care, and traffic congestion monitoring, etc. In such applications, how to ensure the privacy of a participant is important, since incentive mechanisms are used to maintain their enthusiasm for sustainable participation by offering certain amount of reward. In this paper, we propose a pseudonym-based privacy protection scheme, that takes both privacy protection and user incentives into consideration. The proposed scheme uses the pseudonym mechanism and one-way hash function to achieve user incentives, while protecting their identity. We also show extensive analysis of the proposed scheme to demonstrate that it can meet the security and performance the requirement of a participatory sensing application.

• 대한교통학회지
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• 제26권4호
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• pp.111-121
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• 2008

효과적인 가변제한속도(Variable Speed Limit: VSL)는 교통사고를 예방하고 교통정체를 완화시키는데 기여하는 중요한 교통류 제어방안이다. 본 연구에서는 교통사고 예방을 목적으로 가변제한속도를 적용하는 방법론을 제시하였다. 가변제한속도를 적용하는 조건을 두 가지로 분류하였는데, 사고위험도 예측모형에 따른 제한속도 변화와 도로환경조건의 변화에 따른 제한속도 조정 방안을 제안하였다. 예측된 사고위험도에 따른 가변제한속도의 적용은 검지기에서 추출되는 교통량, 속도, 점유율자료와 교통사고자료로 이항로지스틱회귀분석 기법을 사용하여 구축된 사고위험도 예측모형을 사용하였다. 한편, 도로환경조건에 따른 가변제한속도 적용에서는 안개, 폭우, 폭설로 인한 시거제약 상황과 결빙, 비, 눈으로 인한 노면마찰력감소상황 시 최소정지거리 계산을 통해 각 상황에 적용되어야 하는 제한속도를 제시하였다. 이를 바탕으로 통합도로환경조건 모니터링 시스템 하에서 사고위험도와 도로환경조건을 관측하고 제한속도를 변화시키는 가변제한속도 시스템 알고리즘을 제시하였으며, 제안된 알고리즘의 현장 적용 시 고려되어야 할 기술적 이슈를 논의하였다.