• Explosives and Blasting
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• v.39 no.4
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• pp.22-33
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• 2021

Recently, the frequent occurrence of ground subsidence in urban areas has caused increasing anxiety in residents and incurred significant social costs. Among the causes of ground subsidence, the rupture of old water and sewer pipes not only halts the operation of the buried pipes, but also leads to ground and water pollution problems. However, because most pipes are buried after construction and cannot be seen with the naked eye, the importance of maintenance has underestimated compared to other structures. In recent years, integrated physical exploration has been applied to the maintenance of underground pipes and structures. Currently, to investigate the internal conditions and vulnerable portions of the ground, consolidated physical surveys are executed. Consolidated physical surveys are analysis techniques that obtain various material data and add existing data using multiple physical surveys. Generally, in geotechnical engineering, consolidated physical surveys including electrical and surface wave surveys are adopted. However, it is difficult to investigate time-based changes in under ground using these surveys. In contrast, surveys using cosmic-ray muons have been used to scan the inner parts of nuclear reactors with penetration technology. Surveys using muons enable real-time observation without the influence of vibration or electricity. Such surveys have great potential for available technology because of their ability to investigate density distributions without requiring as much labor. In this paper, survey technologies using cosmic ray muons are introduced, and the possibilities of applying such technologies as new physical survey technologies for underground structures are suggested.

• Korean Institute of Interior Design Journal
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• v.20 no.6
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• pp.272-281
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• 2011

The purpose of this study is to analyze the correlation between spatial space structure and visitors' behavior and interpret visitors' behavior concretely from the aspect of exhibition environments. So, this study intends to qualify spatial space structure with integration, connectivity and control value by utilizing space syntax, limit to tracking score among the analysis index and reinterpret with exhibition density and extend of eyesight among the exhibition environments. The results of this study are as follows; First, in case of museums, tracking score shows plus correlation with connectivity and control value among the space syntax variables and very low correlation with integration. In case of art museums, tracking score shows plus correlation with integration and wide variable is judged to more useful to analyze visitor's behavior than minor variable. Second, museums doesn't make a great effect on visitors' behavior from the aspect of extent of eyesight, but from the aspect of exhibition density, visitors relatively watched evenly without short cut at the early stage of exhibition in spite of high exhibition density. And, they conducted short cut as they went to the middle stage of exhibition on the course of watching although the numerical value of exhibition density is low. Third, in case of art museums, visitors' behavior was relatively influenced by exhibition density, not extent of eyesight. But, as they went to the high level on the course of watching, watching speed became rapid and watching length became short in the place the value of extent of eyesight was high. Its reason is judged to be easy to grasp position or space structure of the next exhibition room visually. Therefore, when the concentration of watching is necessary from the aspect of exhibition, to control exhibition density properly before the space is useful to draw visiting to exhibition space afterward.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.453-461
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• 2009

Camera monitoring of topographical changes of intertidal flat was performed at Daehang-ri mud flat outside Semangeum sea dike No. 1, where creation of mud flat was reported after sea dike construction. Ground survey on the mud flat is often limited only to points or few line surveys because of difficulty of walking and limitation of working hours by flood/ebb. This study uses natures of tide that the water lines moving on the intertidal flat during a flood indicate depth contours between low and high tide. Ground coordinates for the water lines extracted from the consecutive images of intertidal flat are calculated and information of topography is acquired by integrating all the water line data. Analysis of 6 camera monitoring data between September 2005 and September 2009 shows 0.127 m deposition per year on the average and variation of deposition/erosion in space and time.

• Economic and Environmental Geology
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• v.40 no.3 s.184
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• pp.307-318
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• 2007

The occurrence of geothermal water has high correlates highly with fossil geothermal system. A fuzzy logic based data integration is applied for geothermal potential mapping in the Southern Gyeongsang Basin which is distributed in the regional fossil geothermal system. Several data sets are related with the origin and distribution of fossil geothermal system, such as the geological map, the density of lineaments, the aerial survey map of magnetic intensity, the map of hydrothermal alteration, the distribution density of hydrothermal mines, which were collected as thematic maps for the integration. Fuzzy membership functions for all thematic maps were compared to the locations of the spa hot springs, which were used as ground-truth control points. After integrating all thematic maps, the results of gamma operator (${\gamma}=0.1$) was showed the highest success rate, and new geothermal potential zone is prospected in some area.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.455-462
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• 2013

This paper introduces the Spatially Preprocessed Speech Distortion Weighted Multi-channel Wiener Filter (SP-SDW-MWF) for multi-microphone noise reduction and proposes a method to determine the speech distortion weights. The SP-SDW-MWF is known as a robust noise reduction algorithm against the error caused by the mismatch in microphones. The SP-SDW-MWF adopts weights which determine the amount of noise reduction at the expense of introducing speech distortion in the noise-suppressed speech. In this paper, we use the error of power spectral density between the estimated signal and the desired signal as the evaluation measure. Thus the a priori SNR is used to control the speech distortion weights in the frequency domain. In the experimental results, the proposed method yields better result in terms of MFCC distortion compared to the conventional method.

• Journal of the Korean Vacuum Society
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• v.18 no.3
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• pp.176-185
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• 2009

The realization and the performance of ICP source are strongly affected by its electrical impedance and the electric/magnetic field distribution. The ICP source impedance is determined by the antenna impedance and the plasma one. It is preferred to keep the imaginary impedance between -100 ohm to 100 ohm, since it should be avoided the high voltage formation on the antenna and abrupt impedance variation during the thin film process. The plasma uniformity is affected by the electric and magnetic field which is formed by the antenna current and voltage. The influence of azimuthal symmetry are shown by the electromagnetic simulation and the measurement result of plasma density. The radial uniformity can be controlled by locating the concentric antennas which have different diameters. The power distribution ratio and its control method are presented in the case of parallel antenna connections.

• Journal of the Korean Geographical Society
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• v.32 no.2
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• pp.141-153
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• 1997

In Korea, cable television(CATV) broadcasting has begun in March, 1995. This Paper aims at examining the location of CATV broadcasting station, and demand density(numbers of viewer houshold) of broadcasting area, and at clarifing the factors affecting subscription. The results are as follows: The number of CATV stations is 54 in 1996, and these CATV stations are mainly located in larger cities. The correlation between the number of established or planned CATV station and the number of household is very high. In sphered broadcasting area Permitted in 1997, the location of CATV station is about 73,000 household and 230,000 persons in the minimum values of household and population, and diameter of sphered broadcasting area is 40.6 km in mean. The factors affecting subscription rates of CATV are median age and supply rates of apartment of each dong in Chongju city and each myun in Chongwon county. The correlation between subscription rates of CATV and supply rates of apartment appears higher than correlation between subscription rates and median age other factors based on residual analysis of regression equation are established period of transmission network of CATV and acceptance attitude of dwellers.

• Journal of the Economic Geographical Society of Korea
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• v.15 no.4
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• pp.752-765
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• 2012

We analyze the relation empirically between regional labor market characteristics and job matching efficiency with the adaption of stochastic frontier production function. Our empirical results suggest that, as both the ratio of 50 years-old-job seekers and the level of spatial density increase, job matching efficiencies also rise. In contrast, an increase in the ratio of firms which offer permanent contracts lowers job matching efficiencies. And the job matching efficiency is relatively higher in metropolitan areas. Finally, We find a negative relation between total industrial production and job matching efficiency, which implies that job seekers tend to accept uncongenial jobs in the recessions.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.2
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• pp.89-101
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• 2017

The study used GIS methods to analyze a business district consisting of traditional markets and large-scale stores, to determine the level of support needed for small enterprises in an urban area of Changwon-si, Gyeongsangnam-do. Data gathered on the area was analyzed using GIS tools such as Kernel density, Network analysis, and Huff modeling. Traditional markets are concentrated in areas where large-scale stores are located, and data analyses show that the number of consumer'use of large-scale stores (157,071) was three times that of traditional markets (59,953). One explanation for these results is that the large-scale stores are located either in densely populated areas or are adjacent to the traditional markets. Therefore, standards and regulations are needed to support small enterprise business districts. In the future, the results of this study can be used as a reference for planning and supporting traditional market business districts.

• Journal of Korean Tunnelling and Underground Space Association
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• v.7 no.4
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• pp.285-294
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• 2005

The behaviors of the ground in crossed zone and the existing upper tunnel in shallow cover due to the excavation of new lower tunnel crossed to that was studied. Model test was performed in the large scale test pit, the size was '$4.0m(width){\times}3.8m(height){\times}4.1m(length)$'. Test ground was constructed uniformly by sand in middle density and test with the crossed angle of $56^{\circ}$ (obliquely) were performed. The numerical analysis was performed on equal condition with model test. Results of the study by model test and numerical analysis show that earth pressure and settlement of the ground in crossed zone were redistributed due to the longitudinal arching effect by the excavation of lower tunnel. Model test shows that upper tunnel blocks stress flow due to the longitudinal arching effect by excavation of lower tunnel.