• Journal of Veterinary Science
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• v.24 no.6
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• pp.78.1-78.6
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• 2023

Avian-origin H3N2 canine influenza A viruses (CIVs) have become enzootic in China and Korea and have sporadically transmitted to North America, causing multiple epidemics. We isolated six CIVs in Korea from CIV-infected patients during 2014-2017 and conducted whole genome sequencing and phylogenetic analyses. Results revealed that CIVs have circulated and evolved in Korea since the early 2000s and then diversified into a new clade, probably contributing to multiple epidemics in China, the USA, and Canada. Our findings bridge an evolutionary gap for understanding the global transmission of CIVs, emphasizing the significance of continuous monitoring of CIVs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1731-1741
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• 2014

Recently, many overpasses, highway, and advanced transit systems have been constructed to distribute the traffic congestion, thus small size of curved bridges with small curvature such as ramp structures have been increasing. Many of early curved bridges had been constructed by using straight beams with curved slabs, but curved steel beams have replaced them due to the cost, aesthetic and the advantage in building the section form and manipulating the curvature of beams, thereby large portion of curved bridges were applied with steel box girders. However, steel box girder bridges needs comparatively high initial costs and continuous maintenance such as repainting, which is the one of the reason for increasing the cost. Moreover, I-type steel plate girder which is being studied by many researchers recently, seem to have problems in stability due to the low torsional stiffness, resulting from the section characteristics with thin plate used for web and open section forms. Therefore, in recent studies, researchers have proposed curved precast PSC girders with low cost and could secured safety which could replace the curved steel girder type bridges. Hence, this study developed a Smart Mold system to manufacture efficient curved precast PSC girders. And by using this mold system a 40 m 2-girder bridge was constructed for a static flexural test, to evaluate the safety and performance under ultimate load. At the manufacturing stage, each single girder showed problems in the stability due to the torsional moment, but after the girders were connected by cross beams and decks, the bridge successfully distributed the stress, thereby the stability was confirmed. The static loading test results show that the initial crack was observed at 1,400 kN when the design load was 450 kN, and the load at the allowable deflection by code was 1,800 kN, which shows that the safety and usability of the curved precast PSC bridge manufactured by Smart Mold system is secured.

• Journal of Korean Society of Steel Construction
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• v.17 no.5 s.78
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• pp.511-518
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• 2005

The behavior of steel curved bridges is more complicated than straight bridges, thus the analysis, design and construction process of curved bridges require much more attention. In design of curved bridges, the grillage analysis using general structural analysis program or special program is mainly used. Comparative study in coherence between these analytical results and actual behavior of curved bridges has been rarely conducted. To study the behaviour of curved bridges and verify the current design method, field measurements and analyses using general structural analysis program and 3-D refined analysis program were carried out for simple and continuous bridges in this study. The study focused on the behavior of curved steel bridges during construction. Measured and analytical results had quantitative difference mutually, but there were qualitatively similar. Stress variations in transverse direction of flange were observed and grillage analysis models yielded more conservative values than 3-D refined analysis models.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.5 s.51
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• pp.11-23
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• 2006

This paper evaluates the seismic response of multi-span prestressed concrete girder bridges typically found in the New Madrid Seismic Zone region of the central United States. Using detailed nonlinear analytical models and synthetic ground motion records for Memphis, TN, nonlinear response history analyses are performed for two levels of ground motion: 10% probability of exceedance (PE) in 50 years, and 2% probability of exceedance (PE) in 50 years. The results show that the bridge performance is very good fur the 10% PE in 50 years ground motion level. However, the performance for the 2% PE in 50 years ground motion is not so good because it results in highly inelastic behavior of the bridge. Impact between decks results in large ductility demands on the columns, and failure of the bearings that support the girders. It is found that making the superstructure continuous, which is commonly performed for reducing dead load moments and maintenance requirements, results in significant improvement in the seismic response of prestressed concrete girder bridges.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.25 no.12
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• pp.830-842
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• 2015

This paper aims to develop a SI(structural identification) technique using the kinetic energy optimization technique(KEOT) and the direct matrix updating method(DMUM) to decide on optimal location of sensors and to update FE model respectively, which ultimately contributes to a composition of more effective SHM. Owing to the characteristic structural flexing behavior of cable bridges, which makes them vulnerable to any vibration, systematic and continuous structural health monitoring (SHM) is pivotal for them. Since it is necessary to select optimal measurement locations with the fewest possible measurements and also to accurately assess the structural state of a bridge for the development of an effective SHM, a SI technique is as much important to accurately determine the modal parameters of the current structure based on the data optimally obtained. In this study, the KEOT was utilized to determine the optimal measurement locations, while the DMUM was utilized for FE model updating. As a result of experiment, the required number of measurement locations derived from KEOT based on the target mode was reduced by approximately 80 % compared to the initial number of measurement locations. Moreover, compared to the eigenvalue of the modal experiment, an improved FE model with a margin of error of less than 1 % was derived from DMUM. Finally, the SI technique for long-span bridges proposed in this study, which utilizes both KEOT and DMUM, is proven effective in minimizing the number of sensors while accurately determining the structural dynamic characteristics.

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.729-734
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• 2002

The effect of several simplified methods of seismic analysis is estimated. The pounding/contacting of superstructures were considered in the multispan simply supported bridge and the multispan continuous bridge. Although nonlinear time history analysis is generally used for seismic analysis of bridges, many codes including AASHTO propose several simplified analysis methods. AASHTO, however, does not mention pounding. Therefore, the simplified methods may produce results that are different from those of nonlinear time history analysis. This study developed nonlinear analytical models of the two types of bridges mentioned. The models were then modified to the simplified linear models for simplified analysis. The results of the simplified methods were compared with those of nonlinear time history analysis. It was found that including of the pounding/contacting element in the simplified methods generated responses similar to those of the nonlinear time history analysis.

• Journal of Satellite, Information and Communications
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• v.10 no.4
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• pp.17-22
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• 2015

High School and College Bridge Program for high school students to learn about specialty training through Mentors with high tech equipment before college admissions has been established. In this study we further developed the previous research experience in 2013 to mentoring program. According to this program, we developed the team learning program and then conducted analytic study on the second year achievement. They became mentees and undergraduate students or graduate course student were mentors. High school students learned how to solve problems by themselves under the mentoring education. The mentees had higher satisfaction in lecture and interest increasing factors at first part of the program. In second part, they showed more satisfaction in new knowledges and recommendation factors. The relationship and intimacy have grown through interaction between mentors and mentees during the team learning. The high school and college bridge program would have significant meaning to develope a customized program for high school students through continuous study.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.1022-1031
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• 2002

This paper presents efficient models for bridge structures using CART-ANFIS (classification and regression tree-adaptive neuro fuzzy inference system). A fuzzy decision tree partitions the input space of a data set into mutually exclusive regions, each region is assigned a label, a value, or an action to characterize its data points. Fuzzy decision trees used for classification problems are often called fuzzy classification trees, and each terminal node contains a label that indicates the predicted class of a given feature vector. In the same vein, decision trees used for regression problems are often called fuzzy regression trees, and the terminal node labels may be constants or equations that specify the predicted output value of a given input vector. Note that CART can select relevant inputs and do tree partitioning of the input space, while ANFIS refines the regression and makes it continuous and smooth everywhere. Thus it can be seen that CART and ANFIS are complementary and their combination constitutes a solid approach to fuzzy modeling.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.10-16
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• 2005

This paper suggested the sulfur lamp power supply using Fuzzy Gain Scheduling(FGS), which was designed and confirmed the performance through manufacturing. it was based on Series Resonant Half Bridge Inverter(SRHBI), so that was applied Pulse Frequency Modulation(PFM), Zero Voltage Switching(ZVS), soft switching and soft start for input power variation and output power compensation. In order to get the lengthened life time of magnetron and stabilized output or power, power ratter and efficiency were improved by fuzzy gain algorism. It also made it possible to get not the existing foxed output power but continuous variable output power$(900\~1250[W])$. The manufactured power supply showed good results in input power $220[V]{\pm}15[\%]$ with stabilized output of power, luminous efficiency 97[1m/W] and power factor $96[\%]$.

• Korean Journal of Environment and Ecology
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• v.20 no.4
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• pp.400-406
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• 2006

To investigate the incidence of the road-kill of amphibians and reptiles in Songgye valley, Woraksan National Park, a survey of Songgye valley was conducted from January, 2003 to December, 2005. Before the investigation, the survey area was divided into 50 sites at 300m intervals. As a result, road-kill by vehicles were confirmed to affect 40% of the amphibians and 68.3% of the reptiles among the total species in the Woraksan National Park. The most affected species was Rana dybowskii, with a frequency of 94.9% among the total number of road-killed Individuals. The highest road-kill rate occurred between April to May, every year. Therefore, it is necessary to construct an eco-bridge and to perform the continuous ecological monitoring for the conservation of R. dybowskii including other species.