• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.79-89
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• 2002

Various geosynthetics used as liners or protection layers are installed in the solid waste landfills. The interface shear strength between geosynthetics installed at the slope of the landfill is a very important variable for the safe design of the bottom and cover systems in the solid waste landfills. The interface shear strength between Geomembrane and Geotexile is estimated by a large direct shear test in this study, The effects of normal stress, water existing between geosynthetics and surface condition of Geomembrae, i.e. smooth or textured, were investigated. The test results show that the effect varied depending on the level of normal stress and the type of geosynthetic combinations. The shear strength was evaluated by the Mohr-Coulomb failure criterion in this research. The shear strength parameters obtained from tests considering the site specific conditions such as normal stress, dry or wet, and surface condition of geosynthetic should be applied to the design of geosynthetics installed at the slope of the landfill to construct a safe solid waste landfill.

• Journal of Navigation and Port Research
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• v.29 no.10 s.106
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• pp.921-926
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• 2005

The purpose of this paper is to conduct a comparative analysis of container terminal operation in Busan and Kwangyang port. The research method used for this study is DEA(Data Envelopment Analysis} and among DEA methods CCR and BCC model has been used. According to the results of CCR model Gamman in 2004 and Gamcheon in 2004 are found to be the most efficient terminals in the sample and the inefficient terminals include Gwangyang Phase 2 terminal. Based on BCC model Gamcheon and Uam are identified as the most efficient terminals in three consecutive years including Gamman terminal in 2004. The inefficient terminals include New Gamman in 2002 and Hutchison in 2002. The research findings show that inefficient terminals need to fully utilise their terminal facilities and increase container throughput through effective marketing activities.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3C
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• pp.83-91
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• 2005

We analyze the performance of an adaptive hybrid search code acquisition algorithm for direct-sequence code division multiple access (DS-CDMA) systems under slowly-moving mobile environments. The code acquisition algorithm is designed to provide the desired feature of constant false alarm rate (CFAR) to cope with nonstationarity of the interference in CDMA forward links. An analytical expression for the mean acquisition time is first derived and the probabilities of detection, miss, and false alarm are then obtained for frequency-selective Rayleigh fading environments. The fading envelope of a received signal is assumed to be constant over the duration of post-detection integration (PDI), considering slow fading environments. Finally, the performance of the designed code acquisition algorithm shall be evaluated numerically to examine the effect of some design parameters such as the sub-window size, size of the PDI, decision threshold, and so on, considering cdma2000 environments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3563-3571
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• 2011

In this research, we analyzed the efficiency of 20 public health centers of Gyeongnam Province during 2007-2009, so weakness of input and output factor were found. We used the CCR, BCC model of Data Envelopment Analysis as a method of evaluation, made a choice human resource as the input variable, made a selection the performance of public health care center, ward as the output variable. The results of this study show that the efficiency of 20 public health centers have got better because Government and Gyeongnam have provided administrative, financial support. It is expected that this research can give good information for effective management of public health centers.

• Tunnel and Underground Space
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• v.28 no.5
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• pp.426-441
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• 2018

Recently, the generalized Hoek-Brown (GHB) failure criterion has been actively employed in various rock engineering calculations, but the analytical form of the corresponding Mohr failure envelope is not available, making it difficult to extend the application of the GHB criterion. In order to overcome this disadvantage, this study proposes a new method to express the tangential friction angle as an explicit function of normal stress by invoking the polynomial best-fitting to the relationship between normal stress and tangent friction angle implied in the GHB failure function. If this normal stress - tangential friction angle relationship is best-fitted with linear or quadratic polynomial function, it is possible to find the analytical root for tangential friction angle. Subsequently, incorporating the root into the relationship between shear stress and tangential friction angle accomplishes the derivation of the approximate Mohr envelope for the GHB criterion. It is demonstrated that the derived approximate Mohr failure envelopes are very accurate in the entire range of GSI value.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.2
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• pp.258-266
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• 2012

Recently, Acoustic Emission (AE) technique is widely applied to develop the early fault detection system, and the problem about a signal processing method for AE signal is mainly focused on. In the signal processing method, envelope analysis is a useful method to evaluate the rolling element bearing problems and Wavelet transform is a powerful method to detect faults occurred on gearboxes. However, exact method for AE signal is not developed yet. Therefore, in this paper, two methods, which is Hilbert transforms (HT) and Hilbert-Huang transforms (HHT), will be compared for development a signal processing method for early fault detection system by using AE. AE signals were measured through a fatigue test. HHT has better advantages than HT because HHT can show the time-frequency domain result. But, HHT needs long time to process a signal, which has a lot of data, and has a disadvantage in de-noising filter.

• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.7-18
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• 2004

There have been various research in analyzing airport productivity such as measuring total factor productivity using the models of translog cost function. DEA(Data Envelopment Analysis) model is very useful in measuring productivity with linear programming when the output is not clearly identified and measured quantitatively in such complex facilities as airport. This study is to measure airport productivity using DEA approach for Northeast Asia. Seven international airports were analyzed including Incheon International Airport in Korea, Cheklapkok Airport in Hongkong, Narita Airport in Japan, and Changi Airport in Singapore. With the productivity measured, we can identify one of the important aspects of comparative advantage in hub competition in Asia.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.4 s.15
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• pp.13-19
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• 2004

The tremendous flood damage caused by Typhoon Rusa(2002) was occurred at GangNeung City in GangWon Province. Almost of the city region was inundated and most of the stream channel facilities were damaged by flash flood with heavy rainfalls. We have investigated seriously damaged parts of stream bank and tried to analyze the causes of damages focused on flow characteristics in curved channel. We analyzed the damage aspects of curved channel by examining geomorphological survey and hydrographical characteristics. Strong correlation was shown according to the regression analysis between length of stream and meander wave length, and meander belt and length of stream. Furthermore, enveloped curve was presented between bottom slope of channel and meander belt, and meander ratio and channel width. As a result, special consideration about stream flow characteristics are needed for engineers who design stream banks and channels.

• Journal of the Korean Society for information Management
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• v.33 no.1
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• pp.139-160
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• 2016

This study suggested improvements after analyzing the effectiveness of "A" university library. So, this study analyzed the effectiveness of E-group "A" university, and measured the effectiveness, classifying with three conditions about input & output and factors and conditions about regional categories. As a result, it is necessary to operate E-group 38 university libraries and "A" University library by increasing input factors to increase outputs. The improvements are as followings. First, it is necessary to stir up member's recognition on libraries. To this, there is a legal system for university library. Second, it is necessary to include library use education in curriculum. Third, it is necessary to prepare complex space so that the members can borrow books and use it for cultural space and rest space.

• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.394-405
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• 2014

Purposes of this study are to find difference in efficiency, productivity change and determinants on efficiency of life insurance industry between pre and post-execution of capital market law on the basis of pre(2005-2008) and post-execution(2009-2012) data. Main results of this research are as follows. First, there was no significant difference of mean value for efficiency between pre and post execution of capital market law. Second, difference of mean value for malmquist index between pre and post execution of capital market law was statistically significant at 5% level. This imply increase in productivity for post-execution of capital market law. Third, one of the important determinant for efficiency was the weight of life planner in both pre and post-execution of capital market law. The weight of life planner had significant positive effect on efficiency.