• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.601-604
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• 2006

Recently the new inorganic sound-absorbing material manufacturing techniques have introduced. These mainly is plentifully used in the place where the noise damage becomes problem in life environment, partitioning of the apartment, the railroad and the express highway, school and the residential quarter neighboring area etc. While the sound-absorbing material has vast quantity of open pore, sound insulation material, used in the apartment and high building in order to prevent the sound between layers, has suitable quantity of closed pore. The fly ash is widely used in the cement materials and the concrete binder material. The bottom ash, however, is rarely used for the grain size is big and multiform with unburning carbon ingredient. In this paper, the practical field tests and the results on the sound reduction properties of formed concrete using bottom ash are described.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.224-231
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• 2005

The ground excavation causes the deformation of the ground where the neighborhood structure is located. The ground deformation result in the vertical settlement of the neighborhood structure as well as the horizontal displacement of the temporary earth retaining structures. The decreased volume of the soil due to the ground settlement is defined as 'the ground loss quantity' or 'the ground loss'. When excavation is performed nearby existing structures, retaining walls should be designed and constructed to minimize the ground loss. Among various methods for reducing the ground loss, this study introduces the pre-loading method which has been recently developed. The reduction effect of the ground loss by pre-loading has been found to be larger as using a wall with relatively smaller rigidity.

• Plant Journal
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• v.7 no.3
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• pp.65-73
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• 2011

This research has suggested a method to select pipe wall thickness by application of the value engineering to reduce the cost and quantity that are major part of construction materials. This research shows that the application of value engineering reduces the cost of piping materials by optimizing pipe wall thickness while maintaining process flow date of design pressure and design temperature. Based on this knowledge, the application of the value engineering will lead to the cost reduction and quantity reduction by effective selection of pipe wall thickness. The application of the value engineering will help the EPC companies to win a contract in the overseas plant market.

• Journal of Industrial Technology
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• v.26 no.B
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• pp.43-51
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• 2006

Through the result of calculating the deviation between the value calculated from two-dimensional number formula, one-dimensional number interpretation, and curving part water surface type calculation method, we could confirmed that the deviation is reduced more than 50% when we use curving part water surface type calculation method. Also it was confirmed that there occurs the reduction rate of maximum 59% as the result of comparing with one-dimensional number interpretation since the reduction rate of safe room height was 20%, in 500 CMS of flood water quantity when we planted the construction of levee by curving part water surface type calculation method. And therefore, we have confirmed that the curving water surface type calculation method can be used as a simple formula in rivers with water quantity less than 500 CMS that flows in and out in Jess than 90 degree angle.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.6
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• pp.623-632
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• 2015

This study proposes a control strategy of the common rail pressure with a fuel injection limitation algorithm to reduce particulate matter (PM) emissions under transient states. The proposed control strategy consists of two parts: injection quantity limitation and rail pressure adaptation. The injection limitation algorithm determines the maximum allowable fuel injection quantity to avoid rich combustion under transient states. The fuel injection quantity is limited by predicting the burned gas rate after combustion; however, the reduced injection quantity leads to deterioration of engine torque. The common rail pressure adaptation strategy is designed to compensate for the reduced engine torque. An increase of the rail pressure under transient states contributes to enhancement of the engine torque as well as reduction of PM emissions by promoting atomization of the injected fuel. The proposed control strategy is validated through engine experiments. The rail pressure adaptation reduced the PM emission by 5-10% and enhanced the engine torque up to 2.5%.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.6
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• pp.117-122
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• 2006

The objective of this study is to analyze the greenroof runoff quantity and delay. The experimental districts, have different soil thickness and vegetation, had installed. A measurement was conducted in Seoul University to investigate the runoff quantity and delay of the greenroof. The measurement point of runoff quality data were 8, located next to each experimental district. Also, the precipitation was measured by rain gauges(# RG2). The experimental investigation lasted from 21th July to 4th December, a total of 137 days. The results showed that the greenroof can contribute runoff retention and delay by soil, but the intensity of actual rain event affected the runoff reduction and delay. Overall, when was the rainy season, percent rainfall retention ranged 17.5% and runoff flow was delayed for 1-3 hours. But on the other hand, when was the typical rain event, percent rainfall retention ranged over 90% and runoff flow was delayed for 1-11 hours. In the result, the greenroof had the greatest runoff retention and delay, while for the typical rain event.

• Journal of Advanced Marine Engineering and Technology
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• v.33 no.3
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• pp.373-377
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• 2009

It is well known that SOx and NOx concentration has a considerable influence on the $N_2O$ emission of the greenhouse gas properties. The quantity of SOx generated during combustion, on fuel specific basis, is directly related to the sulfur content of the fuel oil. However, restricting the fuel oil sulfur content is only a partial response to limiting the overall quantity of SOx emissions, as there remains no over control on the fuel oil consumption other than the commercial pressure which have always directed the attention. This study was carried out as a new basic experiment method of emission control, manly targeted to the vessel. In the experiment, where the scrubbing was achieved through spray tower with high alkaline water made from the electrolysis of seawater, the combined action was to neutralize the exhaust gases (SOx, PM, CO etc.), dilute it, and wash it out. The results showed that SOx reduction of around 95 percent or over could be achieved when using in the high alkaline water, and also leaded to a reduction in the stability of the each pollutant components including the PM (Particulate Matter). The results suggest that the seawater electrolysis method has a very effective reduction of emissions without heavy cost, or catalysts particularly on board.

• Journal of ILASS-Korea
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• v.7 no.1
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• pp.7-13
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• 2002

This paper is study on simultaneous reduction of NOx and soot for direct injection diesel engine using high and low cetane fuels. The stratified injection system was applied for diesel engine to use high and low cetane fuel. In this study, diesel fuel was used as high cetane fuels, methanol was used as low cetane fuels. Some parts of the injection system, ie. Nozzle holder. delivery vale, was remodeled to inject dual fuel sequentially from one injector. The leak injection quantity ratio of dual fuel was certificated by volumetric ratio at injection quantity experiment. According as concentration of low cetane fuel was varied, combustion experiment was performed using Toroidal and Complex chamber. Also, exhaust gas and fuel consumption were measured at the same time. Simultaneous reduction of NOx and soot was achieved at complex chamber regardless of concentration of low cetane fuel. However, according as concentration of low cetane fuel was increased, THC and CO was increased.

• Journal of Educational Research in Mathematics
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• v.10 no.1
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• pp.35-55
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• 2000

There seems to be a public consensus that the content of Korean mathematics textbooks is extensive and of a high level of difficulty. However, such judgment is the result of a generalization based on individual experience or on the results from comparisons of the international levels of achievement. Therefore, a more objective and stricter approach to the determination of the quantity and level of difficulty of mathematics content is necessary. For this purpose, this study has compared the content of Koreas 6th and 7th junior high school curriculums, and the Korean mathematics curriculum to textbooks of the United States, which has a considerable influence on the making of Korean mathematics textbooks. First of all, a comparison of Koreas 6th and 7th junior high school mathematics curriculums showed a slight reduction in the total quantity of content, as more content was deleted than was added in the 7th curriculum. However, given the fact that the number of hours of mathematics classes has been reduced, the reduction in content cannot be regarded as anything more than a simple reflection of the reduction in hours, proving that the 7th curriculum has not met its revision objective of reducing the content by 30%. Meanwhile, the comparison of the United States junior high school mathematics textbooks to Korea's 7th curriculum showed that the 7th grade content in the United States was much broader, encompassing content which in Korea ranged from the 2nd grade of elementary school to the 2nd year of junior high school. Therefore, on the surface, it may appear that the overall level of content in the American mathematics textbook is lower than that of the Korean. However, there are several cafes, such as statistics and probability, where certain content was more difficult and introduced at an earlier grade in the United States than in Korea. In fact, it can be said that Korea students tend to find content of the mathematics textbooks to be harder than they actually are because they are delivered as a mere aggregate of algorithms, with little consideration to its application in their everyday lives. In this respect, there is much room for improvement on the mathematics textbooks of Korea.

• The Journal of Korean Physical Therapy
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• v.16 no.1
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• pp.85-123
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• 2004

Back ground : Subcutaneous fat area is the main factor involved in replacement disease and arteriosclerosis. Simple weight control is the appropriate medical treatment. It's understood that weight reduction does not only reduce the fat concentrations in blood but also reduces blood pressure, improves glucose levels in diabetes patients and reduces incidents of heart disease. there are several methods for reducing fat in the abdominal region but their effectiveness is not folly understood. one method is electrical stimulation of the problem areas. Method : From May 1st 2002 to October 31st. The 15 subjects who received medical examination were aged between 25 and 53 and were of mixed gender. The subjects were divided into two groups one to received functional electrical stimulation and the other a control group. Using Broca's criterion for judging fat grades. I analysed the differences between the two groups before and after the treatment. Subjects received functional electrical stimulation on the abdominal muscle intensity 50Hz. They received this treatment 4 days a week for 40 minutes a day. In the case of aerobic exercise, at the Treadmill, we used it with the intensity of $75\%$ maximum heart rate (220-age). Result 1)After functional electrical stimulation in the case of male subjects, the weight was reduced 1.93kg, obesity $2.60\%$, fat mass 2.73kg, Percent body fat $4.40\%$, waist circumference 6.53cm, circumference of hips 5.53cm. On the other side, the quality of muscle was increased at the rate of 1.03kg, but it's not attentional level. The subcutaneous fat area was reduced by $26.63cm^2$, the visceral fat area was reduced by $43.00cm^2$, In the female subjects, we can see the reduction of fat grade by $26.63cm^2$, the quantity of body fat by 1.5kg, percent body fat by $1.77\%$, circumference of waist by 4.02cm, circumference of hips by 3.67cm, weight by 1.40kg but was increased 0.72kg at the quantity of muscles. We can see the reduction also in the subcutaneous fat area $24.03cm^2$, the visceral fat area by $25.36cm^2$. 2)After aerobic exercise, on the male subjects, we can see reduction of weight by 3.36kg, obesity by $4.00\%$, fat mass by 2.83kg and we can see increase at the soft lean mass by 2.96kg, but we can see reduction, the percent body fat by $3.03\%$, fat distribution by $0.023\%$, circumference of waist by 3.10cm, circumference of hips by 2.23cm. The female subjects show a reduction in the weight by 2.48kg, percent body fat by $2.20\%$, show an increase in the soft lean mass by 1.54kg. We can see a reduction in the quantity of fat mass by 2.32kg, the percent body fat by $2.80\%$, the circumference of waist by 2.16cm, the circumference of hips by 2.68cm, the fat distribution by $0.016\%$, the subcutaneous fat area by $15.25cm^2$ the visceral fat area by $11.52cm^2$. After aerobic exercise, we can't see the attentional change at the total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol. 3)After the application of functional electrical stimulation and aerobic exercise, in result of measurement on the body ingredient, we could see the weight reduction and increase the quantity of muscle with the male group who exercised aerobic. We can see the attentional rate on the electrical stimulation about abdominal fat rate, circumference of waist, circumference of hips. The other hand, I couldn't see the attentional differences between the two groups in the rate of fatness and quantity of body fat and the rate of body fat. There isn't any attentional difference in the area of fat under skin, on the contrary, There is attentional difference in the fat in the internal organs area at the electrical stimulation site. We can't see the attentional change of total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol between electrical stimulation and aerobic exercise. 4)After execution of functional electrical stimulation and aerobic exercise, in result of measurement on change of body ingredient among female objects, We could see weight reduction, increase at muscle quantity in the aerobic exercise group. We could see the attentional differences in the rate of fatness, the rate of abdominal region, the circumference which received electrical stimulation. But, we couldn't see the attentional differences between two groups in the quantity of body fatness, the circumference of hips. The subcutaneous fat area doesn't show the attentional differences. On the Contrary, we could see lots of differences in the visceral fat area of the electrical stimulation group. Conclusion The results show that functional electrical stimulation and aerobic exercise have insignificant differences when if comes to total cholesterol, triglyceride, high density lipoprotein cholesterol, low density lipoprotein cholesterol. Though there is affirmative change in body ingredient after both electrical stimulation and aerobic exercise. Functional electrical stimulation is more effective on the subcutaneous fat area and in changing visceral fat area. There fore. It is concluded that the physical therapy is more effective in the treatment of abdominal fatness.