• Journal of the Korean Geotechnical Society
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• v.24 no.11
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• pp.101-109
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• 2008

In order to investigate the influence of the water on compression characteristic of decomposed granite soils, a single particle crushing test and one-dimensional compression tests were carried out on three decomposed granite soils and Silica sand. The initial fracture strength for single particle reduced and variability of the strength increases due to weakening by existing water. Moreover, it was recognized that one-dimensional compression characteristic was related to the initial fracture strength characteristic, and the initial fracture strength also has the effect of weathering.

• Journal of the Korean Institute of Gas
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• v.3 no.1
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• pp.14-20
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• 1999

This study describes the results of Coefficient of Performance(COP) analysis by cycle simulation for two types of absorption-compression hybrid cycle using the Water/Lithium Bromide solution pair. These types are basic hybrid systems introducing a mechanical compression process into the refrigerant vapor phase of the single effect absorption cycle. In absorption-compression hybrid cycles, coefficient of performance is improved compared with absorption cycle. Hybrid cycle Type 2 is considered as a key technology to support energy utilization system, given its capability of utilizing waste heat to drive system with a high level of efficiency.

• Journal of the Korean GEO-environmental Society
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• v.4 no.3
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• pp.41-49
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• 2003

If MSW(Municipal Solid Waste) landfill is used as a foundation ground of construction site, the change of loading condition may cause a large amount of compression in MSW landfill. Therefore, the reinforcement for the loose compression nature of MSW landfill would be very important design factor to geotechnical engineers in considering the end-use of the landfill. In this study, a possible technique for stabilizing MSW landfill with use of codisposal of municipal solid waste and Fly Ash is discussed. In order to estimate the stabilization of compression characteristic of codisposed landfill, large compression test and lysimeter test were performed. According to the test results, as the proportion of Fly Ash increases, the compression might be reduced, but the permeability might be also reduced. Therefore, it is necessary to take into account the both characteristics changes in real application.

• Journal of the Korean Geotechnical Society
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• v.29 no.3
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• pp.5-13
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• 2013

The compression index, representing the compressibility of clay, is generally obtained from the consolidation test, or predicted by empirical correlations using soil properties. However, empirical methods have regional limitations, because the compression index is affected not only by soil properties but also by site characteristics, such as deposition conditions and stress history. In this study, a method evaluating the compression index from typical soil properties is suggested using the characteristics of reconstituted clay. By analyzing the consolidation test results of Busan clay, the suggested method is verified, and the analysis of prediction error is carried out. It is shown that the proposed method evaluates the compression index more accurately than empirical methods previously suggested. The prediction errors occur by assumption, and are inversely proportional to $e_{cross}/e_0$, obviously.

• Journal of the Korean GEO-environmental Society
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• v.24 no.11
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• pp.41-49
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• 2023

In this study, we analyzed the settlement characteristics of rockfill embankments mixed with soil by confirming the physical properties of soil materials mixed with silty materials and analyzing the compression characteristics of gravel materials according to the mixing ratio of soil materials. For this, we mixed silty materials into sandy soil to analyze the compression characteristics of soil materials, and we constructed a foundation by mixing various ratios of soil into rockfill materials with a particle distribution similar to that of river gravel, and conducted a one-dimensional compression experiment using a medium-sized chamber. As a result of the experiment, in the case of mixed soil materials, the Transition Fine Content (TFC) appeared in the range of 21~26% depending on the load condition, and in the case of rockfill materials mixed with soil, as the void filling ratio of soil in gravel samples increases, both total compression and creep compression decreases, but after a 50% mixing ratio, the settlement of amount increases again.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3090-3095
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• 2008

In this study, variable compression ratio system(VCRS) was applied on the heavy-duty CNG engine and the characteristics of power and emission was investigated according to the increasing of compression ratio. As compression ratio increasing, the increasing of thermal efficiency in direct injection is three times higher than that in port injection. The emission of HC and CO in direct injection is reduced about 14.2%, 17.7% but NOx is increased because of increasing temperature in cylinder.

• Journal of the Korean GEO-environmental Society
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• v.12 no.6
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• pp.43-51
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• 2011

Marine clays are widely distributed in Korean eastern, western and southern coastal areas. Understanding engineering characteristics of the soft ground is very important, whenever civil structures are constructed in those coastal areas. It is because the ground is composed of highly compressible marine clay. In this paper, the physical and compression characteristics of Incheon, Mokpo, Gwangyang and Busan marine clay were analyzed and the characteristics between western and southern coastal marine clays were compared. For this, test results of 1,471 samples from 114 sites were used. As a result, Incheon clay showed the lowest plasticity and the highest unit weight due to influx of silt from the Yellow River and the turn of the tide of Incheon area. However, Gwangyang clay showed highly compressible characteristic due to extensive reclamation. On the other hand, Mokpo and Busan clay showed partially similar levels of characteristics. The compression index of Mokpo and Busan clay was high more than twice in comparison with Incheon clay and that of Gwangyang clay was higher than seventy percents in comparison with Mokpo and Busan clay.

• Journal of the Korea Concrete Institute
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• v.24 no.2
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• pp.129-136
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• 2012

Compression splices are required for all compression members in almost all of the floors in high-rise buildings. Therefore, a clear understanding of the behavior of compression splices can provide a rational design of compression splices. Tests of compression splices with bearing only and bond only cases were conducted to investigate the component resistance characteristics of compression splices. Test results showed that the circumferential tensile stresses induced by bearing and bond overlapped at the end of the splice length deterred bond and bearing splices from developing target splicing strength when both normal bond and bearing splices were used. In particular, the bearing strength was more significantly reduced than the bond strength since the bearing relied on the limited area near the end of the splice length. However, the strength of the normal splice was always higher than the strength of the bond only or the bearing only case. Consequently, the study results showed that splice strength in compression cannot be improved by means of removing bond or bearing. In addition, the bond strength in bond only splices was nearly same as the bond strength in tension splices and the strength increase of compression splice is attributed to end bearing only characteristic.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.6
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• pp.15-21
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• 2010

In the recent years, various researches about the signal processing have been presented to improve the performance of power analysis. Among these signal processing techniques, the research about the signal compression is not enough than a signal alignment and a noise reduction; even though that can reduce considerably the computation time for the power analysis. But, the existing compression method can sometimes reduce the performance of the power analysis because those are the unsophisticated method not considering the characteristic of the signal. In this paper, we propose the new PCA (principal component analysis)-based signal compression method, which can block the loss of the meaningful factor of the original signal as much as possible, considering the characteristic of the signal. Also, we prove the performance of our method by carrying out the experiment.

• Journal of KSNVE
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• v.8 no.5
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• pp.900-907
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• 1998

Rubber materials are extensively used in various machine design application, mainly for vibration/shock/noise control devices. Over the years an enormous effort has been put into developing procedures to provide properties of rubber material for design function. However, there are still a lot of difficulties in the understanding of dynamic characteristics of the rubber components in compression. In this paper, the dynamic characteristics of rubber materials for anti-vibration under compression were investigated. Dynamic and static tests for rubber material with 3 different hardness were performed. In dynamic tests, non-resonance method, impedance method, was used to obtain the complex modulus(storage modulus and loss factor) and the effects of static pre-strain on the dynamic characteristics were investigated. Also, a relation equation between linear dynamic and nonlinear static behavior of rubber material was discussed and its usefulness to predict their combined effects was investigated.