• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.589-599
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• 2021

Purpose: A reliable indicator of congested traffic speed is essential in providing the information of traffic flow states about motorway sections. The aim of this study is to propose an adaptive indicator of congested speed which is employed for deciding the traffic flow states for individual motorway sections using disaggregated section-based speed data. Method: Typically, the state of traffic flow is categorized into the three: uncongested, mixed, congested states. A method, presented in this study, was developed for identifying boundary speed values of road sections through categorizing the three traffic flow states with individual vehicular speed values. The boundary speed state of each road segment is determined using the speed distributions of mixed and congested traffic states. Result: Analysis results revealed that boundary speed values between mixed and congested states for road sections were similar to those of US and EU criteria (i.e., 48.28~66.0 kph). This indicates that boundary speed values could be different according to road sections. Conclusion: It is expected that the method and indicator, proposed in this study, could be efficaciously used for providing ad-hoc real-time traffic states and computing traffic congestion costs for motorway sections in the era of big data.

• The KIPS Transactions:PartA
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• v.13A no.1 s.98
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• pp.79-86
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• 2006

Recently the tagSNP selection problem has been researched for reducing the cost of association studies between human's diversities and SNPs. General approach for this problem is that all of SNPs are separated into appropriate blocks and then tagSNPs are chosen in each block. Marsel in this paper is the system that involved the concept of linkage disequilibrium for overcoming the problem that the existing block partitioning approaches have short of biological meanings. In most approaches, the contiguous regions, which recombinations have LD coefficient |D'| and then tagSNP selection step is performed. And MarSel guarantees the minimum tagSNP selection using entropy-based optimal selection algorithm when tagSNPs are chosen in each block, and enables chromosome-level association studies using efficient memory management technique when input is very large-scale dataset that is impossible to be processed in the existing systems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.4
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• pp.49-57
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• 1992

This study was conducted to evaluate physical property change of asphalt cement chromatograms (by HP-GPC) were experimentally obtained from 3 types of AC-20 virgin ACs, 5 and 24-hour artificially aged ACs, and naturally aged 4 ACs that were recovered from 4 different roads. Absolute viscosity, kinematic visoosity and penetration were the physical properties tested. THF was used for mobil phase and RI detector was used as a detector for Hp-GPC testing. Correlation between each physical property change and the chromatogram variation was evaluated. Each chromatogram was divided into ten-equal-time slices. The percentage areas of 10 slices and each physical property were used for statistical correlation evaluation. Statistical analysis results showed that eaoh physical property had a strong correlation with the chromatogram characteristics. Aging was identified as a mechanism of change of molecular size distribution - increasing large size molecules and reducing coresponding samll size molecules.

• Journal of Wetlands Research
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• v.18 no.2
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• pp.148-153
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• 2016

Hydraulic and hydrological flood routing methods are commonly used to analyze temporal and spatial flood influences of flood wave through a river reach. Hydrological flood routing method has relatively more simple and reasonable performance accuracy compared to the hydraulic method. Storage constant used in Muskingum method widely applied in hydrological flood routing is very similar to the travel time. Focusing on this point, in this study, we estimate the travel time from HEC-RAS results to estimate storage constant, and develop a non-linear regression equation for the travel time using reach length, channel slope, and discharge. The estimated flow by Muskingum model with storage constant of nonlinear equation is compared with the flow calculated by applying the HEC-RAS 1-D unsteady flow simulation. In addition, this study examines the effect on the weighting factor changes and interval reach divisions; peak discharge increases with the bigger weighting factor, and RMSE decreases with the fragmented division.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.155-162
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• 2004

An analytical method to predict the time dependent flexural behavior of composite girder is presented based on sectional analysis. The time dependent constitutive relation accounting for the early-age concrete properties including maturing of elastic modulus, creep and shrinkage is derived in an incremental format by the first order Taylor series expansion. The sectional analysis calculates the axial and curvature strains based on the force and moment equilibriums. The deflection curve of the girder approximated by the quadratic polynomial function is calculated by applying to the proper boundary conditions in the consecutive segments. Numerical applications are made for the 3-span double composite steel box girder which is a composite bridge girder filled with concrete at the bottom of the steel box in the negative moment region. The calculated results are compared with those by finite element analysis results. Close agreement is observed between the two approaches.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.430-435
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• 2006

In this paper, we propose a method based on multimodal biometrics system using the face and signature under ubiquitous computing environments. First, the face and signature images are obtained by PDA and then these images with user ID and name are transmitted via WLAN(Wireless LAN) to the server and finally the PDA receives verification result from the server. The multimodal biometrics recognition system consists of two parts. In client part located in PDA, user interface program executes the user registration and verification process. The server consisting of the PCA and LDA algorithm shows excellent face recognition performance and the signature recognition method based on the Kernel PCA and LDA algorithm for signature image projected to vertical and horizontal axes by grid partition method. The proposed algorithm is evaluated with several face and signature images and shows better recognition and verification results than previous unimodal biometrics recognition techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12B
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• pp.838-846
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• 2005

In this paper, we consider the following two issues for implementing the synchronous Ethernet systems. First, a synchronous Ethernet system employs a fixed size superframe which is divided into a synchronous period and an asynchronous one. We note that the starting point of a superframe is not deterministic when an ordinary data frame's transmission is overlapped the superframe boundary. This overlap may be a fatal drawback for strict jitter bounded applications. Circumventing the problem, we propose a frame fragmentation scheme to provide a zero jitter, and compare its delay performance with the hold scheme which also provides the zero jitter. We next concern that IEEE 802.3x pause frames cannot be promptly transmitted in a synchronous period, and thus asynchronous traffics may be dramatically get dropped at the input buffer of a switch. To handle the problem, we propose an efficient flow control by allowing the transmission of the pause frame in a synchronous period, and investigate the blocking probability of the asynchronous traffics by the simulation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1269-1274
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• 2014

In computer vision research, binarization procedure is one of the most frequently used tools to discriminate target objects from background in grey level binary image. Fuzzy binarization is a reliable technique in environment with high uncertainty such as medical image analysis by setting the threshold as the average of minimum and maximum brightness with triangle type fuzzy membership function. However, this technique is also known as contrast sensitive method thus its discrimination power is not so great when the image has low contrast difference between objects and backgrounds and suffer from information loss as a result. Thus, in this paper, we propose a fuzzy binarization using ART2 algorithm to handle such low contrast image analysis. Proposed ART2 algorithm is applied to determine the medium point of membership function in the fuzzy binarization paradigm. The proposed methods shows low information loss rate in our experiment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1757-1763
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• 2014

Optical wavelength division multiplexing signals of eight non-return-to-zero 10 Gb/s channels were transmitted on the long-haul link up to 720 km. The link span was composed of 80 km single mode fiber, dispersion compensation fiber for complete compensation, and EDFAs. A circulating loop method was applied to the link experiment and the loop was optimized for the transmission link. Wavelength-dependent gain variation of EDFA was compensated using EDFAs of opposite gain slopes without expensive gain flattening filters. Average OSNR was aggravated to 22 dB and the worst OSNR channel variation was 9.7 dB after the transmission. It was confirmed by analyzing optical spectra that this OSNR variation was mainly caused by the hole burning effect of EDFA.

• The Journal of the Acoustical Society of Korea
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• v.34 no.4
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• pp.264-273
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• 2015

Improvement of the radiation beam profile of a medical ultrasonic transducer has been researched in this paper. In order to improve the beam profile, a new transducer structure has been devised that includes both a shaded electrode and a multi-focus lens. For a linear sound source, the beam profile was investigated through finite element analysis, and then the optimal design of the devised structure was carried out by considering such performances as sidelobe level, focal range and beamwidth simultaneously. In the process, the optimal dimension of the devised structure was derived by using the ratio of the focal range to the minimum beamwidth as a performance index. As a result, the beam profile has been improved to have a lower sidelobe level at -20.2 dB and a consistent narrow beamwidth from 30 mm to 160 mm depth with the minimum beamwidth at 2.04 mm. Further, a prototype transducer was fabricated to have the devised structure, and its performance was measured and compared with the analysis results to confirm the validity of the devised transducer structure.