• Proceedings of the Korean Society of Computer Information Conference
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• 2024.01a
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• pp.299-300
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• 2024

첨단 기술의 발전과 함께 지능형 운전자 보조 시스템의 성능 및 교통 시스템 체계가 고도화됨에 따라 전반적인 교통사고 발생 건수는 줄어드는 추세지만 대한민국의 교통사고 발생 빈도는 아직 OECD 평균 대비 높은 실정이다. 특히, 2020년 경제 협력 개발 기구(OECD) 통계에 따르면 대한민국의 인구 10만 명당 교통사고 사망자 수는 회원국 36개 중 29위로 매우 높은 축에 속한다. 따라서, 본 논문에서는 교통사고 발생률을 낮추는 데 도움을 줄 수 있는 주행 이상 패턴 감지 시스템을 제안한다. 제안한 방법에서는 실시간 영상 분석을 통해 신호등 및 차선을 인식함과 동시 차량 내부 진단 데이터에 대한 시계열 분석을 기반으로 운전자의 운전 패턴을 분석한 후 평소와 다른 이상 징후를 발견하면 운전자에게 경고 알림을 제공하여 위험한 상황을 회피할 수 있도록 지원한다.

• Journal of Environmental Health Sciences
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• v.35 no.6
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• pp.461-467
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• 2009

Exposure analysis is a critical component of determining the health impact of pollutants. Global positioning systems (GPS) could be useful in developing time-location information for use in exposure analysis. This study compares four low cost GPS receivers with data logging capability (Garmin 60, Garmin Forerunner 201, GeoStats GeoLogger and Skytrx minitracker MT4100) in terms of accuracy, precision, and ease of use. The accuracy of the devices was determined at two known National Geodetic Survey points. The coordinates logged by the devices were compared when the devices were carried while walking and driving. The Garmin 60 showed better accuracy and precision than the GeoLogger when they were placed at the geodetic points. The Forerunner and Skytrx did not record when they were kept stationary. When the subject wore the devices while walking, the location of the devices differed by about 8 m on average between any two device combinations involving the four devices. The distance between the coordinates logged by the devices decreased when the devices were carried with their antennas facing the sky. All the devices showed similar routes when they were used in a car. All the devices except the Forerunner had satisfactory signal reception when they were worn and when they were carried in the car. The GeoLogger is less comfortable for the subject because of specific wearing requirements. This evaluation found that the Garmin 60 and the Skytrx may be useful in personal exposure analysis studies to record time-location data.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.4
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• pp.181-190
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• 2014

The underwater acoustic lens system is one of the systems getting high-resolution images on the seafloor by the beam forming method using acoustic lens. The beam forming using acoustic lenses reduces complexity and driving power. When receiving an incoming beam with the acoustic lens array, beam pattern analysis and arrangement problem of the array sensor must be addressed. Introducing SIR (Signal to Interference Ratio), the relationship among sensor interval, beam pattern and image quality would be analyzed. Generally if the sensor interval getting wider, the less effect of the side lobes makes SIR high. If the amplitude of a side lobe is high, SIR is generally getting low. The type of the apodization function changes the width, shape and amplitude of both main lobe and side lobes. Thus an appropriate apodization function can improve SIR. In this paper, SIR is stable at the sensor interval of 13mm with 0-10dB, which is not high relatively. By applying the Chebyshev function, the SIR becomes 80dB over the sensor interval of 37 mm or higher. The Hann and triangular functions demonstrate better SIR when the sensor interval becomes narrower.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.163-170
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• 2005

Urban transit is a complex system that is combined electrically and mechanically, it is necessary to construct maintenance system for securing safety accompanying high-speed driving and maintaining promptly. Expert system is a computer program which uses numerical or non-numerical domain-specific knowledge to solve problems. In this research, we intend to develop the expert system which diagnose failure causes quickly and display measures. For the development of expert system, standardization of failure code classification system and creation of BOM(Bill Of Materials) have been first performed. Through the analysis of failure history and maintenance manuals, knowledge base has been constructed. Also, for retrieving the procedure of failure diagnosis and repair linking with the knowledge base, we have built RBR(Rule Based Reasoning) engine by pattern matching technique and CBR(Case Based Reasoning) engine by similarity search method. This system has been developed based on web to maximize the accessibility.

• Journal of Convergence for Information Technology
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• v.7 no.6
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• pp.97-102
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• 2017

In this paper, we have interested in cooperative intelligent transport system and autonomous driving system, and focused on analysis of the characteristics of Cooperative Awareness Message (CAM) and Decentralized Environmental Notification Basis Service (DENM) message, which is key delivery message among cooperative intelligent transport system (C-ITS) characteristics for research objectivity. For research method, we also described V2X communication, and also analyzed the security certificate and header structure of CAM and DENM messages. We described CAM message, which is a message informing the position and status of the vehicle. And the DENM message is presented a message informing an event such as a vehicle accident, and analysis security communication, which is supported services. According to standard analysis result, 186 bits or 275 bits are used. In addition to the security header and the certificate format used for vehicle communication, we have gained the certificate verification procedure for vehicles and PKI characteristics for vehicles. Also We derived the characteristics and transmission capability of the security synchronization pattern required for V2X secure communication. Therefore when it is considered for communication service of DENM and CAM in the C-ITS environment, this paper may be meaningful result.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.153-172
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• 2018

Overloading of Commercial vehicles have been an important area of transportation as one of the main causes of pavement damage, bridge collapse, severe traffic accident, etc. In this study, we analyzed the effects of overweight prevention by analyzing overweight driving patterns and using weight sensors. First, we analyzed relevant literatures of overweight and surveyed the commercial weight sensors. Then we chose the typical type of overweight vehicles based of overweight enforcement data analysis. MEMs inclinometer weight sensor were installed to 10 test vehicles and data was collected by weight sensors and gps in real time. As a result of gross vehicle weight and axle weight analysis, it was found weight sensor could decrease overweight rate. However, since the number of samples of test vehicles is insufficient to represent the whole commercial vehicle, further studies are deemed possible through the extension test.

• Journal of Astronomy and Space Sciences
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• v.25 no.4
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• pp.415-424
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• 2008

Kwak et al. (2008) found that the mean neutral wind pattern in the high-latitude lower thermosphere is dominated by rotational flow than by divergent flow. As an extension of the our previous work (Kwak et al. 2008), we performed a term analysis of vorticity equation that describes the driving forces for the rotational component of the horizontal wind in order to determine key processes that causes strong rotational flow in the high-latitude lower thermospheric winds. For this study the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM) is used. The primary forces that determine variations of the vorticity are the ion drag term and the horizontal advection term. Significant contributions, however, can be made by the stretching term. The effects of IMF on the vorticity forces are seen down to around 105-110km.

• Journal of Digital Convergence
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• v.16 no.3
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• pp.157-167
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• 2018

The shortage of research in Vietnam port evolvement is uncontroversial although a huge amount of investment is observed to upgrade both quantity and quality. This study examines the port system performance, in the context of spatially concentration ratio, in Southern Vietnam for the period 2007-2016, by using prevailing indicators for spatially concentration assessment including concentration ratios (CR), the Herfindahl-Hirschman index (HHI), the Gini coefficient, the Lorenz curve and shift-share analysis (SSA), a trend of deconcentration is described in Southern Vietnam port system, since the traditional ports to new deep-water ports. Also, driving forces of this shifting would be discussed in detail. Implications from this study would enable not only port administrators, port operators but also shipping lines, cargo owners, logistics service providers to comprehensively understand the growth of the port system in Southern Vietnam.

• International Journal of Fluid Machinery and Systems
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• v.5 no.3
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• pp.134-142
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• 2012

The competition to deliver ultra-low emitting vehicles at a reasonable cost is driving the automotive industry to invest significant manpower and test laboratory resources in the design optimization of increasingly complex exhaust after-treatment systems. Optimization can no longer be based on traditional approaches, which are intensive in hardware use and laboratory testing. The CFD is in high demand for the analysis and design in order to reduce developing cost and time consuming in experiments. This paper describes the development of a comprehensive practical model based on experiments for simulating the performance of automotive three-way catalytic converters, which are employed to reduce engine exhaust emissions. An experiment is conducted to measure species concentrations before and after catalytic converter for different loads on engine. The model simulates the emission system behavior by using an exhaust system heat conservation and catalyst chemical kinetic sub-model. CFD simulation is used to study the performance of automotive catalytic converter. The substrate is modeled as a porous media in FLUENT and the standard k-e model is used for turbulence. The flow pattern is changed from axial to radial by changing the substrate model inside the catalytic converter and the flow distribution and the conversion efficiency of CO, HC and NOx are achieved first, and the predictions are in good agreement with the experimental measurements. It is found that the conversion from axial to radial flow makes the catalytic converter more efficient. These studies help to understand better the performance of the catalytic converter in order to optimize the converter design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1593-1598
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• 2011

The purpose of this study is to perform parameter selection and develop a method for the condition monitoring of an LCD conveyance robot. To determine the vibration characteristics of the driving part of the robot, the gear mesh frequency (GMF) of the speed-reducing gearbox is calculated and confirmed by frequency analysis. In order to ensure reproducibility of the measured data, an appropriate working pattern is selected and experiments are carried out. For condition monitoring of the robot, a wireless measurement system is constructed and used in parameter selection, with the GMF as the center. A method involving the use of the standard deviation of the measured data and another method involving the use of multiple value of amplitude are proposed.