• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.4
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• pp.137-145
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• 2012

Sand is one of the essential materials used for social infrastructure construction such as embankment, landfill and backfill. It was known that mechanical properties and shear strength of sand are closely related to relative density. Therefore it is very important to determine accurate relative density. In this study, Portable Cone Penetration Tester (PCPT) was used to estimate the relative density and the internal friction angle of sand. PCPT cone-tip resistance ($q_c$) was measured changing the relative density of the two soil samples.Standard sand (JMJ) and Busan sand (BS). Also, a direct shear test was performed to investigate relationship between relative density and internal friction angle. The size and shape of soil particles were confirmed by using Scanning Electron Microscope (SEM). As a result, the log value of $q_c$ was linearly correlated with relative density and internal friction angle. In particular, the internal friction angle of BS sample was greater than that of JMJ, which was due to difference of the shape and mean size of particles. This result shows that it is important to determine the shape and size of particles as well as relative density to define mechanical property of sand. Through this study, it can be more effectively and conveniently to investigate relative density and shear strength of sand by using PCPT in situ.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.5
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• pp.92-97
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• 2011

This paper deals with the improvement of electrode installation for measurement of ground resistance through investigation on the spot in buildings. The investigation was carried out for an earthing terminal board for measurement of ground resistance, installation of auxiliary electrode, etc. The criteria value is set up by measuring method of ground resistance in international standard. In case of inadequate installation of auxiliary electrode, a relative error is analyzed and adequate installation method of auxiliary electrode is proposed. As a consequence, it is necessary to write direction of ground and equipment, and separate auxiliary electrode for measurement of ground resistance in order to minimize measuring error.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.96-102
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• 2009

In this paper, the effects of the position and the angle of the potential probes on the measurements of the ground resistance with the fall-of-potential method are described and the testing techniques to minimize the measuring errors are proposed. The fall-of-potential method is theoretically based on the potential and current measuring principle and the measuring error is primarily caused by the position and angle of auxiliary probes. In order to analyze the relative error for measuring value of ground resistance due to the position of the potential probe, ground resistance were measured in case that the distance of current probe was fixed at 50[m] and the distance of potential probe was located from l0[m] to 50[m]. Also, the potential probe was located at 30[$^{\circ}$], 45[$^{\circ}$], 60[$^{\circ}$], 90[$^{\circ}$] and 180[$^{\circ}$]. As a consequence, relative error decreased with increasing the distance of potential probe and decreasing the angle between current probe and potential probe. The results could be help to determine the position of potential probe when the ground resistance was measured at grounding system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.206-207
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• 2006

This paper describes the dielectric analysis of several insulators for home appliances. The dielectric characteristics of ABS(acrylonitrile butadiene styrene) were tested in relative permittivity, dielectric loss($tan{\delta}$) and specific resistance and compared with those of the other 4 insulators of PE(polyethylene) series. As a result, the relative permittivity of only the ABS slightly decreased with temperature. In the case of the tan6, the ABS showed higher dielectric loss than the other insulators but more excellent thermal performance. In addition, its changing pattern in specific resistance was very similar to that in $tan{\delta}$.

• Journal of the Society of Naval Architects of Korea
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• v.60 no.5
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• pp.305-319
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• 2023

This study focuses on measuring the relative wave elevation around the KSUPRAMAX-O ship and comparing it with numerical analysis results (potential and computational fluid dynamics). The relative wave elevation is a good indicator of the pressure distribution on the ship's surface, which is affected by the ship's motion, incident waves, and distributed waves. Prior to measuring the relative wave elevation, a comparative test was conducted on resistance type, capacitance type, and ultrasonic type wave probe to measure the relative wave elevation, and it was confirmed that the resistance type wave probe was suitable for measuring the relative wave elevation. A model test was performed at low speed and design speed using resistance type wave probe and compared with the results of numerical analysis result. As for the motion response, it was confirmed that the result of experiments and the result of the numerical analysis were in good agreement. The relative wave elevation showed a similar trend between the experiment and the computational fluid dynamics, but the potential analysis result showed a difference from the experiment in design speed.

• The Journal of Information Systems
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• v.27 no.2
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• pp.53-75
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• 2018

Purpose The purpose of this study is to provide implications by examining the factors affecting the consumers' innovation resistance and intention to use FIDO technology based on the innovation resistance model. In addition, we investigate the difference between FIDO group using biometric authentication technology and those using knowledge / possessive authentication technology. Design/methodology/approach This study investigated the factors influencing innovation resistance and intention to use based on the innovation resistance model. And the structural equation model was applied to analyze the effect of innovation resistance and intention to use. Findings According to empirical results, this study found that perceived relative advantage (+), perceived risk (+), perceived complexity (+), and existing product attitude(+) influenced innovation resistance, and perceived relative advantage (+), self efficacy(+), and innovation resistance(-) influenced intention to use. In addition, this study found that there is a significant difference between the group using the bio-based authentication technology and the group using the knowledge / possessive based authentication technology.

• Journal of Environmental Policy
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• v.1 no.1
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• pp.91-110
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• 2002

Ecosystem health assessment is an emerging concept regarded as a useful diagnostic tool for evaluating ecosystems. The stability of ecosystem is the main theme in the assessment. Generally, two components - resilience and resistance - are involved in the mechanism of ecosystem stability. In this study, relative degrees of the resistance and the resilience were quantified for most aquatic Insects Inhabiting running waters in Korea. A total of 34 groups were newly categorized based on previous studies, and a conceptual model has been produced. The model was applied for the aquatic insect communities inhabiting different streams and demonstrated that each stream ecosystem possessed different degrees of stability. This study also indicated that it was possible to compare stabilities of different ecosystems using relative degrees of resilience and resistance. Using the conceptual model, suitable conservation and management strategies could be recommended in ecological assessments. The model can be used as a stepping-stone for developing more comprehensive methodology that objectively diagnoses and evaluates the ecosystem stability.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.5
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• pp.782-792
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• 2004

The effects of sealing solution for anodized Mg-Al alloys and their corrosion resistance property were investigated. focusing on the effects of anodizing potentials aluminum contents and sealing solutions. All of the anodized specimens showed better corrosion resistance than that of non-anodized specimens, regardless of applied potentials. It was found that the anodic film formed at 4 V had the best corrosion resistance. The sealing effects were improved by increasing the temperature of distilled water. the pH of solution and the relative intensity ratio of $Mg(OH)_2$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.2
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• pp.107-114
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• 1989

Model pile pull-out tests have been executed to investigate the characteristics of the critical relative displacement at which the critical pile skin resistance is mobilized. Test result shows that the critical relative displacement is neither constant nor pile size dependent, but it is the most closely related with the magnitude of the critical skin resistance. The empirical relationship between the two quantities has been established. Behavior of centrifuge physical models of skin-resistance-related problems has been investigated on a quantitative basis by a computational method. A pile downdrag problem has been employed as an example of the skin-resistance-related problems. A simple transfer function type method has been developed for the analysis of the downdrag. It is concluded from the analysis that centrifuge physical modeling of skin-resistance-related problems may lead to an erroneous result on an unconservative side, as may have been expected due to the violation of the similarity rule by the quantity of the critical relative displacement.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.517-524
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• 2001

In this study, the effect of relative density and fine contents(Finer then # 0.08mm sieve) on liquefaction phenomenon in reclaimed land by hydraulic hammer compaction is analyzed. For more site-specific studies, reclaimed land in Inchon International Airport is selected and the cyclic triaxial tests are performed on disturbed samples. In cyclic triaxial tests, the characteristics of reclaimed land in Inchon International Airport are considered sufficiently. The liquefaction resistance stress ratio ($\tau$$\ell$/$\sigma$v') can be defined by relative density 40, 50, 60, and 70% and also by fine contents : 0, 10, 20, 30, and 40% under relative density (D$\_$r/) 50% used disturbed samples. From tile result of comparing tile cyclic triaxial tests, it is shown that the liquefaction strength of soil increases with increases of relative density and fine contents. Fspecially fine contents is the main factor affecting the liquefaction potential. In addition, the liquefaction resistance stress ratio is reduced by the increase of fine content and tile ratio of change is steep until fine contents 20% and that is flexible during the range of fine contents 20% to 40%. Through this study, it is proved that the soil characteristics (fine contents 5∼20%) of the reclaimed land in Inchon International Airport flays an important role in the reduction of liquefaction potential.