• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.2
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• pp.116-124
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• 2003

• Journal of the korean Society of Automotive Engineers
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• v.8 no.3
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• pp.46-54
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• 1986

Driving pattern of gasoline passenger car was measured and analyzed at some areas(6urban area routes, 4 radial routes, 4 circular routes)in Seoul city. Measured items were vehicle speed, engine speed, intake manifold vacuum, and fuel consumption. Driving pattern data were reappearanced with engine dynamometer. Results of this investigation might be summarized as below; 1. When we compared urban area route with radial or circular route in rush hour, it was found that the average vehicle speed was measured to be lower about 25% and fuel consumption to be higher about 12% in urban area route. 2. Average vehicle speed was measured to be higher about 30% and driving resistance output to be higher about 25% in non-rush hour, but average fuel economy was increased a little. 3. On the bases of average fuel economy and characteristics of exhaust emissions, optimum driving vehicle speed was found about 60 km/h in the 4th(top)and about 40km/h in the 3rd in driving of experimental engine. 4. Idling frequency and exhaust emissions of CO,HC were related to idling closely. But exhaust emission of NOx, which had nothing to do with idling frequency, had relation to acceleration time ratio.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.1-10
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• 1998

In this paper, we investigated the improvement of characteristics of knock, emission and fuel consumption rate by optimizing the location and size of water transfer holes in cylinder head gasket without change of engine water jacket design itself. The cooling system was modified in the direction of reducing the metal temperature in the head and increasing the metal temperature in the block. The optimization of water transfer holes in cylinder head gasket was obtained by "flow visualization test". The water transfer holes were concentrated in front side of the engine in order to reduce thermal boundary layer in the water jacket of No. 2 and No. 3 combustion changer in the cylinder head, which would have a large knock intensity, and increase thermal boundary layer in the water jacket of the cylinder block. When the modified coolant flow pattern was applied as proposed in this paper, the knock characteristic was improved. The spark timing was advanced up to 2$^{\circ}$ in low and middle speed range at a full load. In addition, HC emission at MBT was reduced by 5.2%, and the fuel consumption rate was decreased up to 1% in the driving condition of 2400 rpm and 250 KPa. However, since this coolant flow pattern mentioned in this paper might deteriorate the performance of vehicle cooling system due to the coolant flow rate reduction, a properly optimized point should be obtained. obtained.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.4
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• pp.466-476
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• 2012

This study calculated monthly and sectoral (for industry, energy industry, transport, residential, commercial and public sectors) greenhouse gas (GHG) emissions of Seoul, Korea from 1999 until 2009 with following the IPCC 2006 Guideline for National Greenhouse Gas Inventories through an analysis on available monthly data of fossil fuel and electricity consumption for the period. The time series analysis showed that GHG emissions had significant cyclical pattern season by season with the highest peak in August and the lowest peak in January throughout the period. The analysis on monthly and sectoral energy consumption showed that residential, commercial and public sectors had emitted about 65% of total GHG emissions of Seoul and had consumed more energy in winter for heating. About 30% GHG of Seoul was emitted from transport sector but its monthly energy consumption showed irregular pattern and it consumed 80% petroleum (in 2009) of Seoul. Hopefully together with further study on this subject, it is expected that this study can be used as basic data for various research regarding Greenhouse gas baseline emission, energy consumption pattern and estimation for future GHG emission of Seoul.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3943-3948
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• 2022

Single-photon emission computed tomography is one of the reliable pin-by-pin verification techniques for spent-fuel assemblies. One of the challenges with this technique is to increase the total fuel assembly verification speed while maintaining high verification accuracy. The aim of the present study, therefore, was to develop an artificial intelligence (AI) algorithm-based tomographic image analysis technique for partial-defect verification of fuel assemblies. With the Monte Carlo (MC) simulation technique, a tomographic image dataset consisting of 511 fuel-rod patterns of a 3 × 3 fuel assembly was generated, and with these images, the VGG16, GoogLeNet, and ResNet models were trained. According to an evaluation of these models for different training dataset sizes, the ResNet model showed 100% pattern estimation accuracy. And, based on the different tomographic image qualities, all of the models showed almost 100% pattern estimation accuracy, even for low-quality images with unrecognizable fuel patterns. This study verified that an AI model can be effectively employed for accurate and fast partial-defect verification of fuel assemblies.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1064-1069
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• 2014

The use of emulsified fuel and EGR (Exhaust gas recirculation) system are effective methods to reduce NOx emission from diesel engines. In general, it is considered that EGR method influences diesel engine combustion in three different ways: thermal, chemical and dilution effect. Among others, the thermal effect is related to the increase of specific heat capacity due to the presence of $CO_2$ and $H_2O$ in inlet air. Meanwhile, emulsified fuel method of utilizing latent heat of vaporization and miro-explosion has been recognized as an effective technique for reducing diesel engine emissions. In this paper, an author studied on combustion and emission characteristics by using emulsified fuel (EF, Light oil : 80% + Water : 20%) and EGR (30% EGR ratio) system. And the effect of fuel injection pattern control was investigated.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.1
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• pp.73-81
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• 2011

The performance of emission factor has been validated by comparison with on-road test data. Emission factor, which is a function of vehicle speed, has been acquired based on chassis dynamometer test with NIER driving pattern. Portable Emission Measurement System, PEMS has measured on-road emission. Test vehicle was operated on defined test routes under different driving conditions, and made ten trips along its route. Emission factors properly simulate on-road test result, although there is some drawback to consider variety of driving condition on real world. Vehicle specific power and acceleration have been used to explain the distributed on-road result within same vehicle speed range. The trend in carbon dioxide and nitrogen oxide emission with respect to specific power and acceleration is clear. It has been found that specific power is a good explanatory variable for microscopic analysis for modal test result. Acceleration is good for microscopic as well as macroscopic analysis.

• Journal of the Korean association of regional geographers
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• v.11 no.6
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• pp.559-570
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• 2005

The purpose of this paper is to estimate the effect of population change on waste emission in the case of Busan City. The results are as follows : First, population and waste emission in Busan City Show decreasing pattern since 1995. According to increase or decrease of population and waste emission, The 16 Gus in Busan City are categorited into 5 types. Comparing the difference of population and waste emission between 1995 and 2003, we find out a similar trend by 16 Gus in Busan City. Second, the waste emission shows the positive relation with the number of population and the land by use. But there exists multicollinearity between population and the land by use, and the population is considered the main factor of waste emission. Third, the population causes 92% or more of the waste emission in Busan City, and future researches are required for the additional causes of waste generation.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.796-801
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• 2001

During cold operation period, fuel injection system directly contributes the unburned hydrocarbon formation in spark ignition engines. The relationship between injection parameters and HC emission behavior was investigated through a series of experiments. Spray behavior of port fuel injectors was characterized through a quantitative evaluation of mass concentration of liquid fuel by a patternator and PDA. 6-hole injector was found to produce finer spray than single hole one. Using a purpose-built test rig, the wall wetting fuel was measured, which was mostly affected by wall temperature. Varying coolant temperature($20{\sim}80^{\circ}C$), HC emissions were measured in a production engine. With respect to the different types of injectors, HC emission was also measured. In the 6-hole injector application, the engine produced less HC emission in low coolant temperature region. Though it produces much more amount of wetting fuel, it has the advantages of finer atomization quality. In high coolant temperature region, there was little effect between different types of injectors. The control schemes to reduce HC emissions during cold start could be suggested from the findings that the amount of fuel supply and HC emission could be reduced by utilizing fine spray and high intake wall temperature.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.2
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• pp.32-37
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• 2001

This article is to provide reasonably accurate vehicle emission estimates for the four sampled fuels which are commercially available across the nation. Emission quantities are obtained by testing a vehicle on a chassis dynamometer and capturing a sample of the emissions from the tailpipe in vehicle. The vehicle is driven following a particular pattern of idle, acceleration, cruise, and deceleration. Shown here is the trace of the test cycle known as the CVS-75 Mode which is used to certify the emission performance standards. The mode of CVS-75 consists of a cold start cycle, a hot stabilized cycle, and a hot start cycle. Emissions for the pollutants are measured in vehicle testing. These are carbon monoxide (CO), oxides of nitrogen (NOx), and total hydrocarbon (THC). The test results summarized in this report indicate that the differences for the amount of emission are quantitatively minimal.