• Journal of the Korean earth science society
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• v.42 no.2
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• pp.149-163
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• 2021

In this study, the changes in ozone (O3) concentrations due to the removal of power plant emissions were analyzed using a community multi-scale air quality (CMAQ) model. Two different CMAQ model simulations, one considering the emissions from the Hadong power plant and one without considering the emissions, were conducted to investigate the effect of the emissions on the changes in the O3 concentrations in the surrounding areas. Subsequently, the CMAQ simulations exhibited an increase in the O3 concentration (25.24%) despite a decrease in the NOx (-18.87%) and volatile organic carbon (VOC, -11.27%) concentrations, which are major O3 precursors. The changes in the NO and O3 concentrations due to the removal of power plant emissions presented a strong negative correlation (r= -0.72). This indicated that the increase in the O3 concentration was mainly attributed to the significantly decreased NO concentration, thus, mitigating the O3 titration reaction (NO+O3→NO2+O2). Additionally, due to the VOC-limited (i.e., NOx-saturated) conditions in the study region, NO affected the O3 concentration, indicating that the O3 concentrations in a particular region are not only proportional to the increase or decrease in emissions. Therefore, an in-depth understanding of the chemical O3 production and loss in a particular region is necessary to accurately evaluate the effect of emission control on the changes in the O3 concentration.

• Journal of Ocean Engineering and Technology
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• v.21 no.2 s.75
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• pp.67-74
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• 2007

Maritime and Ocean Engineering Research Institute (MOERI), a branch of KORDI, has designed and manufactured a model of an autonomous underwater vehicle (AUV) named ISiMI (Integrated Submergible for Intelligent Mission Implementation). ISiMI is an AUV platform to satisfy the various needs of experimental test required for development of challenging technologies newly investigated in the field of underwater robot; control and navigational algorithms and software architectures. The main design goal of ISiMI AUV is downsizing which will reduce substantially the operating cost compared to other vehicles previously developed in KORDI such as VORAM or DUSAUV. As a result of design and manufacturing process, ISiMI is implemented to be 1.2 m in length, 0.17 m in diameter and weigh 20 kg in air. A series of tank test is conducted to verify the basic functions of ISiMI in the Ocean Engineering Basin of MOERI, which includes manual control with R/F link, auto depth, auto heading control and a final approach control for underwater docking. This paper describes the implementation of ISiMI system and the experimental results to verify the function of ISiMI as a test-bed AUV platform.

• International Journal of Concrete Structures and Materials
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• v.10 no.sup3
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• pp.97-108
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• 2016

When the energy performance of concrete is substantially higher than that of normal type concrete, such concrete is regarded as energy efficient concrete (WBSCSD 2009). An experimental study was conducted to investigate mechanical properties of energy efficient concrete with binary, ternary and quaternary admixture at different curing ages. Slump test for workability and air content test were performed on fresh concretes. Compressive strength, splitting tensile strength were made on hardened concrete specimens. The mechanical properties of concrete were compared with predicted values by ACI 363R-84 Code, NZS 3101-95 Code, CSA A23.3-94 Code, CEB-FIP Model, EN 1991, EC 2-02, AIJ Code, JSCE Code, and KCI Code. The use of silica fume increased the compressive strengths, splitting tensile strengths, modulus of elasticities and Poisson's ratios. On the other hand, the compressive strength and splitting tensile strength decreased with increasing fly ash.

• 한국연소학회:학술대회논문집
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• 2001.11a
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• pp.169-178
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• 2001

Among the recent research ideas to reduce hydrocarbon emissions emitted from SI engines till light-off of catalyst since cold start are those exploiting non-thermal plasma technique and photo-catalyst that draws recent attention by virtue of its successful application to practical use to clean up the atmosphere using the feature of its relative independence on temperature. Based on the previous research results obtained with model exhaust gases using an experimental emissions reduction system that utilizes the non-thermal plasma and photo-catalyst technique, further investigation was conducted on a production N/A 1.5 liter DOHC engine during cold start to warm-up. For the effects of non-thermal plasma-photocatalyst combined reactor, 10% concentration reduction was achieved with the fuel component paraffins, and the large increase in non-fuel paraffinic components and acetylene concentrations were similar to those of base condition. However the absolute value was locally a bit higher than those of base condition since the products was made from the dissociation and decomposition of highly branched paraffins by plasma-photocatalyst reactor. Olefinic components were highly decomposed by about 75%, due to these excellent decompositions of olefins which have relatively high MIR values, and the SR value was 1.87 that is 30% reduction from that of base condition, then, the photochemical reactivity was lowered.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.5
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• pp.523-531
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• 2012

The performance simulation of a desiccant rotor, which is a core component of a desiccant cooling system, was conducted on the basis of a theoretical solution of the heat and mass transfer process in the rotor. The simulation model was validated by comparing simulation results with experimental data; reasonable agreement was observed. The effect of the rotation speed on the performance of the desiccant rotor was investigated for various operation conditions: temperature (50 to $70^{\circ}C$), humidity ratio (0.01 to 0.02 kg/kg DA), and flow rate of regeneration air. The optimum rotation speed was determined from the maximum moisture removal capacity (MRC) of the desiccant rotor, and it was found to vary with the operation conditions. Further, the correlation for the optimum rotation speed was determined by regression analysis.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.313-336
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• 2007

Unlike a conventional railway system, a high-speed rail system experiences various aerodynamic problems in tunnel sections. Trains running at a high speed in a small tunnel, when compared with the open field, face significant air pressure, resulting in reduced operating stability and fast change in pressure inside the tunnel. These phenomena further cause some unexpected problems such as the passengers onboard feeling an aural discomfort and an impulsive noise at the tunnel exit. To solve these problems, this paper introduces analysis of aerodynamic characteristics for determination of tunnel cross section. The optimum cross-section that satisfies the criteria of aural discomfort was reviewed through lots of numerical simulation analysis. Also, the pressure inside the passenger car of a train operating on Kyungbu HSR line was measured, and the pressure inside the tunnel and the micro-pressure waves at tunnel exit were measured at Hwashin 5 Tunnel. At the same time, a test of train operation model was performed and then the measurement results and test results were compared to verify that various parameters used as input conditions for the numerical simulations were appropriate.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.347-350
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• 2006

Maritime and Ocean Engineering Research Institute (MOERI), a branch of KORDI, has designed and manufactured a model of an autonomous underwater vehicle (AUV) named ISiMI(Integrated Submergible for Intelligent Mission Implementation). ISiMI is an AUV platform to satisfy the various needs of experimental test required for development of challenging technologies newly investigated in the field of underwater robot; control and navigational algorithms and software architectures. The main design goal of ISiMI AUV is downsizing which will reduce substantially the operating cost compared to other vehicles previously developed in KORDI such as VORAM or DUSAUV. As a result of design and manufacturing process, ISiMI is implemented to be 1.2m in length, 0.17m in diameter and weigh 20 kg in air. A series of tank test is conducted to verify the basic functions of ISiMI in the Ocean Engineering Basin of MOERI, which includes manual control with R/F link, auto depth, auto heading control and a final approach control for underwater docking. This paper describes the implementation of ISiMI system and the experimental results to verify the function of ISiMi as a test-bed AUV platform.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.2
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• pp.129-139
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• 2004

The several assumptions and design parameters to determine the ventilation rate in tunnel ventilation system were examined. In longitudinal ventilating tunnel, the ventilation rate has been determined by the critical velocity above which the smoke propagation to the upstream of ventilating air is prevented. Based upon the examination of assumptions and experimental results, we suggested the improved method to determine the critical velocity. In transverse ventilating tunnel, we found that the ventilation rate has been determined in accordance with the custom rather than fire-smoke dynamics such as the critical velocity in the longitudinal ventilating tunnel. It is because the ventilation rate in the transverse ventilation system has been determined by considering only the ventilation of contaminant by vehicle. To improve the ventilation design parameters based upon the fire-smoke dynamics, we conducted model tunnel fire experiments. From the experimental results, smoke propagating distance and smoke filling were suggested as the design parameter to determine the ventilation rate in transverse ventilating tunnel. And tunnels in Europe designed by the custom is found to have the dangerous nature in view of fire safety.

• Applied Biological Chemistry
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• v.32 no.1
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• pp.1-7
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• 1989

The autoxidation products derived from methyl linolenate are isolated and characterized by using thin-layer chromatography, infrared, ultraviolet and nuclear magnetic resonance spectrometries. In addition, the propriety of the application of NMR spectrometry to the analysis of the autoxidation products is examined. Spectroscopic data indicate that the autoxidation of methyl linolenate produces hydroperoxides and trans, cis-substituted diene. The autoxidation products have a predominant cis, trans-conjugated diene system with some trans, trans-configuration. The spectroscopic data of ir, uv, and nmr are very consistent with each other, and further investigation of the multiplet region at $5.83{\sim}6.60ppm$ would be very helpful for the structural elucidation of the autoxidation products.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.183-191
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• 2015

If the damage analysis on river-side facilities such as dam, river bank structures and bridges caused by disasters such as typhoon, flood, etc. becomes available, it can be a great help for disaster recovery and decision-making. In this research, We tried to extract a Digital Surface Model (DSM) and analyze the accuracy from Unmanned Air Vehicle (UAV) images on river-side facilities. We tried to apply stereo image-based matching technique, then extracted match results were united with one mosaic DSM. The accuracy was verified compared with a DSM derived from LIDAR data. Overall accuracy was around 3m of absolute and root mean square error. As an analysis result, we confirmed that exterior orientation parameters exerted an influence to DSM accuracy. For more accurate DSM generation, accurate EO parameters are necessary and effective interpolation and post process technique needs to be developed. And the damage analysis simulation with DSM has to be performed in the future.