• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.2 s.72
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• pp.213-219
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• 2006

Topology optimization problem requires numerous repeated evaluations of objective function and design sensitivity for elements within design domain with various density distributions. The recently proposed two-level condensation scheme(TLCS) is very promising for the construction of reduced system and for an accurate and efficient analysis concerned about eigenvalue and dynamic problems. We used the two-level dynamic condensation scheme for the analysis and sensitivity computation part in the structural topology optimization problem. The results of the topology optimization for the reduced system show the TLCS provides high accuracy and computation efficiency compared to the full scale system within engineering accuracy.

• Korean Journal of Adult Nursing
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• v.18 no.2
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• pp.213-222
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• 2006

Purpose: This study was designed to construct a structural model for explaining model health-related quality of life in acquired people with physical disabilities. Method: The hypothetical model of this study was consisted of 6 latent variables and 14 observed variables. Exogenous variables included in this model were physical status and economical level. Endogenous variables were social attitudes, family function, self-esteem, and health-related quality of life. Data were collected from 226 acquired people with physical disabilities residing in Seoul and Kyunggi-do from January to February, 2005. The collected data were analyzed using SAS 8.2 version and LISREL 8.32 version program. Results: The results of the fitness test of the modified model were follow as; ${\chi}^2=67.479$ (df=50, p=.05), GFI=.959, AGFI=.914, SRMR=.049, NFI=.961, NNFI=.979, CN=249.244. Health-related quality of life was influenced directly by physical status, economic level, and social attitudes and accounted for 88.8% of the variance by these factors. Conclusion: These results suggest that physical status is the most significant effect on health-related quality of life, and social attitudes and economic level are important factors having influences on health- related quality of life. Therefore improving physical status and economic level, and modifying negative attitudes are necessary to increase health-related quality of life of acquired people with acquired physical disabilities.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.345-353
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• 2012

Recently rapid urbanization facilitates development of high-rise building complex including apartment and office building in urban area. Many problems related with high-rise building are reported. Especially, unpleasant strong winds in pedestrian area are frequently encountered around the high-rise building. CFD simulation methods are used to analyze the wind environment of pedestrian level in high-rise building block. However the results show differences between CFD and measurement. The reason for the difference is that conventional CFD simulation couldn't consider the effect of trees, shrubs and plants which affect the wind environment. Canopy model is a solution to solve the limitation of CFD analysis. In this paper, the canopy model to predict wind environment of pedestrian level by CFD simulation will be proposed and the validity will be analyzed by comparison of measurement and CFD prediction.

• Structural Engineering and Mechanics
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• v.63 no.2
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• pp.259-268
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• 2017

In this paper, the incremental nonlinear dynamic analysis is used to evaluate the seismic performance of steel moment frame structures. To this purpose, three special moment frame structure with 5, 10 and 15 stories are designed according to the Iran's national building code for steel structures and the provisions for design of earthquake resistant buildings (2800 code). Incremental Nonlinear Analysis (IDA) is performed for 15 different ground motions, and responses of the structures are evaluated. For the immediate occupancy and the collapse prevention performance levels, the probability that seismic demand exceeds the seismic capacity of the structures is computed based on FEMA350. Also, fragility curves are plotted for three high-code damage levels using HASUS provisions. Based on the obtained results, it is evident that increase in the height of the frame structures reduces the reliability level. In addition, it is concluded that for the design earthquake the probability of exceeding average collapse prevention level is considerably larger than high and full collapse prevention levels.9.

• Tunnel and Underground Space
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• v.11 no.1
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• pp.14-19
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• 2001

The estimation of proper prediction method and the transformation method of environmental regulation standard were carried out by measuring blasting vibration. Vibration velocity was more adequate than vibration level in the blasting design by scaled distance. Thus, design and construction mutt be controlled by vibration velocity, and it is required that the vibration velocity is transformed to vibration level to meet regulation standard. Three transformation methods were studied. First, transformation formula is derived from the shock vibration data only. The second method it the transformation by correlation equation of vibration velocity and vibration level measured at the same time. The last one is the transformation of vibration velocity by FFT. It seems to be difficult to estimate damages by these methods because that every method shows considerable error. But transformation formula of PPV component to vibration level was most practical.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.259-262
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• 2003

In the Republic of Korea, Ministry of Construction & Transportation and Korea Water Resources Corporation manage the national groundwater monitoring network at the 169 stations and will organize the supplementary groundwater monitoring network at the 10,000 stations by 2011 year. The method that organizes the monitoring network was developed using the Analytic Hierarchy Process with pairwise comparison. Several estimation factors for the estimating every district were selected to reflect each district conditions. Their weighting value was decided by pairwise comparison and questions to the experts about groundwater The optimal number of groundwater monitoring well was calculated through the developed method. To verify this method, groundwater was monitored in Jeonju city by way showing the example. The study area In Jeonju city needs 7 stations for the supplementary groundwater monitoring network. The results monitored in 7 stations inferred the groundwater level around the study area by Kriging. The mean of residual between inferred groundwater level value from Kriging and actual groundwater level is rather low. Furthermore, the mean and standard deviation of residual between inferred groundwater level change and actual groundwater change is much lower. The Fact that 7 monitoring stations are sufficient for observing the groundwater condition in the study area makes it possible for suggested monitoring number to be proper.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.3
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• pp.224-229
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• 2009

Partial safety factors(PSFs) for Level I reliability based design of caisson type quay walls were calculated. First order reliability method(FORM) based PSFs are the functions of sensitivities of limit state function with respect to design random variables, target reliability index, characteristic values and first moment of random variables. Modified PSFs for water level and resilient water level are newly defined to keep consistency with the current design code. In the numerical example, PSFs were calculated by using a target reliability index. Seismic coefficient is defined to show extreme distribution. It was found that PSFs for seismic coefficient becomes smaller as the return period for design seismic coefficient grows longer.

• ETRI Journal
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• v.40 no.5
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• pp.664-676
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• 2018

Given the rapidly increasing market penetration of photovoltaic (PV) systems in many fields, including construction and housing, the effective maintenance of PV systems through remote monitoring at the panel level has attracted attention to quickly detect faults that cause reductions in yearly PV energy production, and which can reduce the whole-life cost. A key point of PV monitoring at the panel level is cost-effectiveness, as the installation of the massive PV panels that comprise PV systems is showing rapid growth in the market. This paper proposes an implementation method that involves the use of a panel-level wireless PV monitoring module (WPMM), and which assesses the cost-effectiveness of this approach. To maximize the cost-effectiveness, the designed WPMM uses a voltage-divider scheme for voltage metering and a shunt-resistor scheme for current metering. In addition, the proposed method offsets the effect of element errors by extracting calibration parameters. Furthermore, a design method is presented for portable and user-friendly PV monitoring, and demonstration results using a commercial 30-kW PV system are described.

• Journal of Digital Convergence
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• v.9 no.2
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• pp.141-152
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• 2011

The data center has become an increasingly important part of most business operations. An increasing demand for computation has led to increasing industry energy consumption. Therefore, higher-than-normal rates of energy efficiency have become a core issue in the life cycle of data center. In this paper, we proposed the framework of level diagnosis for green data centre that can be used to diagnose the levels of capability maturity model. This framework contains the 5 key areas such as construction, air-conditioning, electricity, information technology, organization and indicators that can be applied as basic level diagnosis guide for green data center.

• Journal of The Korean Association For Science Education
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• v.21 no.4
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• pp.668-676
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• 2001

In order to comprehend the internal processes of heterogeneous small-group cooperative learning in science class, this study investigated verbal interaction patterns by the achievement level. Frequency of verbal behaviors was compared in respect of the achievement level, and participation patterns and characteristics were investigated. Verbal interaction patterns by the achievement level were also analyzed based on students' perceptions of interactions. It was found that there were no significant frequency differences between high- and medium-achieving students' verbal behaviors. The verbal interaction patterns showed co-construction processes between high- and medium-achieving students, which was consistent with the students' perceptions of interactions. These suggested that medium-achieving students actively participated in small-group interactions in science class.