• International conference on construction engineering and project management
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• 2013.01a
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• pp.231-234
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• 2013

According to the recent development of USN technology, it has been applied in various fields of construction management. In particular, the concrete curing management using the wireless measurement system is actively being conducted. However, the existing method has limitations such as the reinstallation of temperature sensors and repositioning of repeaters. It is also not easy to acquire the measured data. Thus, this study focuses on the concrete curing management. This study proposes data acquisition method using the smartphone on construction site and tests applicability of the data measuring device and the smartphone. The test allows us to suggest the actual communication distance on construction site and to determine the correction value that is applied to the measured temperature. The data acquisition method proposed in this study is intended to enable appropriate management on construction site and will be able to be applied effectively to a variable construction site. It can also be used in all fields of construction management.

• Korean Journal of Construction Engineering and Management
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• v.23 no.5
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• pp.34-42
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• 2022

Construction site layout is attracting attention as efficient use of construction site space greatly affects the duration and cost of the overall construction. Therefore, there are many studies that automate and optimize construction site layout planning. However, the usability of construction site, which consists of goal variables of the studies, has still been unknown. Therefore, the authors present the evaluation criteria for usability of construction site layout and evaluate the usability of domestic construction sites through user survey. Furthermore, the difference in usability between construction site managers and construction site workers was confirmed. As a result of the survey, domestic construction site layout had a low effectiveness and had the lowest score in the environment category. In addition, construction site workers scored lower overall than construction site managers. Through such usability evaluation results, it contributed to the construction site layout theory by assessing current construction site layout practice and suggesting an improvement direction for automating site layout planning.

• Geomechanics and Engineering
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• v.37 no.6
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• pp.539-554
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• 2024

This study explores development of prediction model for seismic site classification through the integration of machine learning techniques with horizontal-to-vertical spectral ratio (HVSR) methodologies. To improve model accuracy, the research employs outlier detection methods and, synthetic minority over-sampling technique (SMOTE) for data balance, and evaluates using seven machine learning models using seismic data from KiK-net. Notably, light gradient boosting method (LGBM), gradient boosting, and decision tree models exhibit improved performance when coupled with SMOTE, while Multiple linear regression (MLR) and Support vector machine (SVM) models show reduced efficacy. Outlier detection techniques significantly enhance accuracy, particularly for LGBM, gradient boosting, and voting boosting. The ensemble of LGBM with the isolation forest and SMOTE achieves the highest accuracy of 0.91, with LGBM and local outlier factor yielding the highest F1-score of 0.79. Consistently outperforming other models, LGBM proves most efficient for seismic site classification when supported by appropriate preprocessing procedures. These findings show the significance of outlier detection and data balancing for precise seismic soil classification prediction, offering insights and highlighting the potential of machine learning in optimizing site classification accuracy.

• Korean Journal of Construction Engineering and Management
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• v.18 no.5
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• pp.41-49
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• 2017

The ordering organizations of civil engineering project manage the construction site indirectly because the construction site is mostly located at a remote location and the public official also manages many sites. Since the civil engineering project has a wide working area, it is not easy to know the status of the whole project quickly by the indirect management method by report of the field practitioner. In order to solve these problems, the field management system between the ordering organization and the field office is changing from offline to online. This study suggests an advanced construction site management system that obtains site-related 3D information with the use of UAV and shares the information between the construction site in remote locations and their supervising authorities. To develop an UAV application system, the problems of field management in many actual sites were analyzed and derived necessary functions such as status reporting and online information management. The developed system was applied to actual field to verify its usability and compared the efficiency improvement with existing field management method.

• Journal of Environmental Science International
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• v.25 no.9
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• pp.1329-1339
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• 2016

The purpose of this study was to obtain the basic data needed to identify the impact of the odor, emitted from the Ochang Scientific Industrial Complex area on the surrounding residential areas by measuring and confirming odor compounds. The analysis showed that complex odors were diluted from around 4 to 1. The offensive odor measurement results showed that among the sites, site 1 was highest in sulfur compounds, site 2 was highest in toluene, site 3 was highest in trimethylamine, and site 4 was highest in buthylaldehyde. It cannot be decided to be odor-causing compounds for higher odor concentration because each odor substance has a different odor threshold value. According to the odor contribution analysis for each site, site 1, site 2, and site 4 contained high buthylaldehyde concentrations, and site 3 had a high level of trimethylamine. It could be determined that highly evaluated substances were main causes to result in substance for each site.

• Earthquakes and Structures
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• v.14 no.4
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• pp.285-295
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• 2018

In this study, the effect of local site conditions (site class and site amplifications) and structural variability are investigated on fragility functions of typical building structures. The study area is chosen as Eastern Turkey. The fragility functions are developed using site-specific uniform hazard spectrum (UHS). The site-specific UHS is obtained based on simulated ground motions. The implementation of ground motion simulation into seismic hazard assessment has the advantage of investigating detailed local site effects. The typical residential buildings in Erzincan are represented by equivalent single degree of freedom systems (ESDOFs). Predictive equations are accomplished for structural seismic demands of ESDOFs to derive fragility functions in a straightforward manner. To study the sensitivity of fragility curves to site class, two sites on soft and stiff soil are taken into account. Two alternative site amplification functions known as generic and theoretical site amplifications are examined for these two sites. The reinforced concrete frames located on soft soil display larger fragilities than those on stiff soil. Theoretical site amplification mostly leads to larger fragilities than generic site amplification more evidently for reinforced concrete buildings. Additionally, structural variability of ESDOFs is generally observed to increase the fragility especially for rigid structural models.

• BMB Reports
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• v.29 no.5
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• pp.448-454
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• 1996

Bacteriophage ${\phi}FC1$ is a temperate phage which was identified as a prophage in the Enterococcus faecalis KBL703 chromosome. Phage ${\phi}FC1$ integrates into the host chromosome by site-specific recombination. The phage attachment site P (attP) was localized within the 0.65-kb XhoI-HindIII fragment and the nucleotide sequence of the region was determined. An open reading frame (mj1) which adjoined the phage attachment site encoded a deduced protein related to the site-specific recombinase family. The organization of this region was comparable to other site-specific recombination systems. The molecular weight of the expressed MJ1 in E. coli was in good agreement with the predicted 53,537 Da of the mj1 gene product. Elucidation of the phage-specific integration process in this study would provide useful genetic tools such as a chromosomal integration system.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.2
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• pp.91-101
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• 2016

This study is the compared seismic performance that are difference between the performance of structures on various site classes and beam-column connection. this analysis model was designed the previous earthquake load. To compare the performance levels of the structure was subjected to nonlinear static and nonlinear dynamic analysis. Nonlinear analysis was used to The Perform 3D program. Nonlinear static analysis was compared with the performance point and Nonlinear dynamic analysis was compared the drift ratio(%). Analysis results, the soft site class of the displacement was more increase than rock site classes of the displacement. Also The smaller the displacement was increased beam-column connection stiffness.

• Advances in environmental research
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• v.3 no.2
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• pp.173-183
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• 2014

A comprehensive mathematical model was developed for this study to estimate on-site and off-site GHG emissions from wastewater treatment plants (WWTPs). The model was applied to three different hybrid WWTPs (S-WWTP, J-WWTP, and T-WWTP) including anaerobic, anoxic, and aerobic process, located in Seoul City, South Korea. Overall on-site and off-site GHG emissions from S-WWTP, J-WWTP, and T-WWTP were $305,253kgCO_2e/d$, $282,682kgCO_2e/d$, and $117,942kgCO_2e/d$, respectively. WWTP treating higher amounts of wastewater produced more on-site and off-site GHG emissions. On average, the percentage contribution of on-site and off-site emissions was 3.03% and 96.97%. The highest amount of on-site GHG emissions was generated from anoxic process and the primary on-site GHG was nitrous oxide ($N_2O$). Off-site GHG emissions related to electricity consumption for unit operation was much higher than that related to production of chemicals for on-site usage. Recovery and reuse of biogas significantly reduced the total GHG emissions from WWTPs. The results obtained from this study can provide basic knowledge to understand the source and amount of GHG emissions from WWTPs and strategies to establish lower GHG emitting WWTPs.

• Structural Engineering and Mechanics
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• v.36 no.1
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• pp.111-127
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• 2010

This paper studies the effects of spatially varying ground motions on the responses of a bridge frame located on a canyon site. Compared to the spatial ground motions on a uniform flat site, which is the usual assumptions in the analysis of spatial ground motion variation effects on structures, the spatial ground motions at different locations on surface of a canyon site have different intensities owing to local site amplifications, besides the loss of coherency and phase difference. In the proposed approach, the spatial ground motions are modelled in two steps. Firstly, the base rock motions are assumed to have the same intensity and are modelled with a filtered Tajimi-Kanai power spectral density function and an empirical spatial ground motion coherency loss function. Then, power spectral density function of ground motion on surface of the canyon site is derived by considering the site amplification effect based on the one dimensional seismic wave propagation theory. Dynamic, quasi-static and total responses of the model structure to various cases of spatially varying ground motions are estimated. For comparison, responses to uniform ground motion, to spatial ground motions without considering local site effects, to spatial ground motions without considering coherency loss or phase shift are also calculated. Discussions on the ground motion spatial variation and local soil site amplification effects on structural responses are made. In particular, the effects of neglecting the site amplifications in the analysis as adopted in most studies of spatial ground motion effect on structural responses are highlighted.