• The Journal of Engineering Geology
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• v.17 no.4
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• pp.567-576
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• 2007

In order to assess the on-site applicability of 3D absolute displacement monitoring of tunnel using digital photogrammetry, the displacement of the optical target placed at the measurement section was investigated, as planned in the OO tunnel construction site. The targets on 3 measurement lines only were considered for each point of measurement for the reconstruction of 3D cubic model for the digital vision monitoring. For each 3D model, 3 or more images have to be obtained at each point. On the last 2 measurement lines, 6 targets (crown, left and right walls) were continuously overlapped to construct 3D models so that 6 or more apices can be shared by 2 3D models. In order to compare the measurement methods of 3D absolute displacements in tunnel excavation, i. e, total station and digital image measurement, both the digital image measurement and optical measurement were conducted for 10 times in the same work section. The time and measurement results of both methods were compared.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.101-108
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• 1997

A pair of piezoelectric transducers was developed for geotechnical site characterization in rock materials. SH-wave measurement capability of the transducers can provide a more complete characterization. The performance of the transducers was tested at a limestone site.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.7-16
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• 2015

PURPOSES : This study was performed to determine a systematic approach for measuring the coefficient of thermal expansion (COTE) of concrete specimens. This approach includes the initial calibration of measurement equipment. Test variables include coarse aggregate types such as natural aggregate, job-site produced recycled concrete aggregate, and recycled aggregate processed from an intermediate waste treatment company. METHODS : First, two cylindrical SUS-304 specimens with a known COTE value of $17.3{\times}10^{-6}m/m/^{\circ}C$. were used as reference specimens for the calibration of each measurement system. The well-known AASHTO TP-60 COTE apparatus for concrete measurement was utilized in this study. Four different measurement apparatuses were used with each LVDT installed and a calibration value was determined using each measurement apparatus. RESULTS : In the initial experimental stage, calibration values for each measurement apparatus were assumed to be almost identical. However, using the SUS-304 samples as a reference, the calibration values for the four different measurement apparatuses were found to range from 3.49 to $8.86{\times}10^{-6}m/m/^{\circ}C$. Using different adjusted values for each measurement apparatuses, COTE values for the three different concrete specimens were obtained. The COTE value of concrete made with natural coarse aggregate was $9.91{\times}10^{-6}m/m/^{\circ}C$, that of job-site produced recycled coarse aggregate was $10.45{\times}10^{-6}m/m/^{\circ}C$, and that of recycled aggregate processed from the intermediate waste treatment company was $10.82{\times}10^{-6}m/m/^{\circ}C$. CONCLUSIONS : We observed that the COTE value of concrete made from recycled concrete aggregates (RCA) was higher than that of concrete made from natural coarse aggregate. This difference is due to the fact that the total volumetric mortar proportion in the RCA mix is higher than that in the concrete mix made with natural coarse aggregate.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.65-71
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• 2019

Conventional methods of measuring ground resistance and ground resistance field measurement are used to measure voltage drop according to the resistance value of the site by applying current by installing a constant interval of measurement electrode. If the stratified structure of the site site is unique, errors in boundary conditions will occur in the event of back acid and the analysis of the critical ground resistance in the ground design will show much difference from simulation. This study utilizes the Arduino module and smart ground measurement technology in the convergent information and communication environment to develop a reliable smart land resistance measuring device even if the top layer of land is unique, to analyze the land resistance and accumulate data to predict the change in the age of the land. Considering the topographical characteristics of the site, we propose a ground resistance measuring device and its method of measuring ground resistance so that the auxiliary electrode can be installed by correctly positioning the angle and distance in measuring ground resistance. Not only is ground resistance value obtained through electrodes installed to allow accurate ground resistance values to be selected, but it can also be used as a useful material for installing electrical facilities in similar areas. Moreover, by utilizing reliable data and analyzing the large sections of the site, a precise analysis of the site, which is important in ground design as well as construction cost, is expected to be used much in ground facility design such as potential rise.

• Journal of Multimedia Information System
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• v.8 no.1
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• pp.11-16
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• 2021

This study developed a design to estimate the location of rescue demander using the sound system at disaster site, in the conditions of indoor positioning cannot be performed properly. It is a location tracing system through smart phone application. It generates sound wave information of rescuer at the rescue site, and it can be used as assistant means for indoor location tracing at the disaster site using sound wave receiving measurement technology.

• Journal of Korean Society of Forest Science
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• v.88 no.3
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• pp.285-291
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• 1999

Loblolly(Pinus taeda L.) and slash(Pinus elliottii Engelm.) pines are the most important timber producing species in the Southern United States. Site index equations to estimate site index curves(base age 25 years) for loblolly pine and slash pine plantations have been developed based on long-term repeated measurement data sets. To check magnitude of errors in estimating site index, each cumulative measurement cycle data sets and all combined data sets were used to recalculate site index values. The Chapman-Richards' growth function was selected for stand height prediction. Anamorphic base age invariant site index curves were presented based on this height prediction equation. Statistics used in the evaluation were mean of the differences and mean of the absolute differences. For plantation ages less than 5 years, site index values showed very sensitive fur both species based on the evaluation test.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.4
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• pp.91-98
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• 1997

At present, automated monitoring of water quality in Han river has been operated at each water treatment plant. But the automated measurement sites must be choosen newly because water source in Seoul move to the upper stream of Chamshil weir. In this study, automated monitoring sites in Han river were reviewed, and the proper sites for automated monitoring of water quality have been selected by Qual2E model, RMA model, water sampling guidline, Sanders' method and topograpical characteristics of Han river in order to resonable operate. 8 sites have been selected as follows: (1) the site of immediately after Paldang drainage (2) the left site and a right site of $Gu{\check{u}}i$ water intake (3) the left site and a right site at Noryangjin(Han river bridge) (4) the site between Shingok weir and Anyangchun confluence point(Hangju bridge) (5) the site of Chungryangchun downstream(existence) (6) the site of Tanchun downstream(existence) (7) the site of Anyangchun downstream(existence) (8) the site of Wangsukchun downstream. The results proposed resonable operating management of network and economical system built up.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.1 no.1
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• pp.14-19
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• 1990

A site attenuation measurement system has been developed and evaluated. The system uses selfresonant dipole antennas and baluns. Using the system we measured the site attenuations of the KSRI open area test site. The measured results agree with calculated data within $\pm$3dB , so the site can be used for EMI/EMC measurements and antenna calibrations.

• Korean Journal of Materials Research
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• v.17 no.7
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• pp.358-360
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• 2007

Cobalt subtitution on NiSi is investigated by using an ab-initio calculation. Firstly, a relaxed NiSi structure is calculated and the calculated lattice parameters are compared with experimentally determined lattice parameters. The calculated values are smaller than the experimental values by about 2%. As the calculation is based on 0 K, and the experimental measurement is performed at room temperature, those values are in good agreement. Next, a Co atom substitutes a Ni and Si site, respectively, to evaluate the preferable site between them. Co prefers Ni site to Si site. The calculated total energy also indicates that the Co substitution to Ni site stabilizes the NiSi structure. Therefore, the thermal stability of NiSi with Co addition can be achieved by the structure stabilization of NiSi by Co substitution into Ni site of NiSi.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.43-51
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• 2014

Angular distortion due to differential settlement is one of the critical factors which influences on the stability and serviceability of a structure. The angular distortion criterion proposed by Bjerrum is generally used in practice. However, the measurement system used in field especially a road embankment site did not properly represent the angular distortion of a structure. The problem was related to the shortage and not proper installation of measurement gauges, and the incorrect understanding of the basic concept of angular distortion in interpretation of measurement data. These things were reveled by analyzing the measured data in the road embankment site. An improved measurement system has been suggested as a so-called "relative displacement measurement system" between columns with automatic measurement.