• Earthquakes and Structures
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• v.23 no.3
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• pp.245-257
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• 2022

This study is a basic study on the seismic reinforcement method of anchors of fixed parts in order to reduce the effect of seismic motion that affects the facilities in the event of an earthquake. By applying the test method of ICC ES AC 156, a seismic simulation experiment was performed on the vibration table with three axes simultaneously using the number of connecting bolts between cabinets and channels as a parameter. In addition, the reliability of the experiment was verified using numerical analysis, and the part about the dynamic characteristics that could not be performed according to the experimental limit was investigated through numerical analysis. As a result of the experiment, it was confirmed that the natural frequency of the main body was increased due to the increase in the number of connecting bolts between the cabinet-channel. Accordingly, it was judged that the rigidity of the lower part of the cabinet was increased due to seismic reinforcement. It was analyzed that the impact delivered to the body was effectively reduced. In the future, if the reinforcement of the connection parts mentioned in this study is added to the existing seismic reinforcement of the electrical cabinets, it is expected that the damage to the electrical cabinets of the power plant equipment caused by an earthquake will be effectively reduced.

• Korean Journal of Construction Engineering and Management
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• v.18 no.5
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• pp.11-19
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• 2017

The purpose of this study is to analyze the efficiency of PV according to installation condition in the complex type buildings. For this purpose, annual performance of solar power generation in a certain area was investigated and various methods were conducted including post operation evaluation. In addition, we tried to find out influencing factors that affect the efficiency and sought to identify their relative impact of degree through the data analysis and site visits together. In the middle of this process we can draw up major considerations for the efficient photovoltaic power generation installation. In the mean while, previous studies are making something new related with method for efficiency enhancement and individual influential factors based on experimental environment rather than the empirical data site based. As a result of the study, it was confirmed that even if installed in the same area, the power generation efficiency is 1.5 times as high as the installation condition. Furthermore, statistical analyses were performed on azimuth, tilted angle and shade, which are variables affecting conversion efficiency, and it was statistically confirmed that all variables are meaningful factors that affect the conversion efficiency which is a dependent variable. The most influential factor is the azimuth, followed by the tilted angle and the shade factor. From this result, we expect to be able to provide installation guidelines for the solar power generation equipments on the rooftop zone.

• Journal of Cadastre & Land InformatiX
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• v.51 no.2
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• pp.169-184
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• 2021

Recently, land cover spectral libraries have been widely used in studies to classify land cover based on hyperspectral images. Overseas, various institutions have built and provided land cover spectral libraries, but in Korea, the building and provision of land cover spectral libraries is insufficient. Against this background, the purpose of this study is to suggest the possibility of using domestic and foreign spectral libraries in the classification studies of domestic land cover. Band matching is required for comparative analysis of the spectral libraries and land cover classification using the spectral libraries, and in this study, an automation logic to automatically perform this is presented. In addition, the directly constructed domestic land cover spectral library and the existing overseas land cover spectral library were comparatively analyzed. As a result, the directly constructed land cover spectral library had the highest correlation coefficient of 0.974. Finally, for the accuracy evaluation, aerial hyperspectral images of the study area were supervised and classified using the domestic and foreign land cover spectral libraries using the SAM technique. As a result of the accuracy evaluation, it is judged that Soils, Artificial Materials, and Coatings among the classification items of the foreign land cover spectral library can be sufficiently applied to classify the cover in Korea.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.83-92
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• 2016

The purpose of this study is to evaluate the seismic performance of domestic unreinforced masonry(URM) buildings using nonlinear dynamic analysis. For that, the nonlinear hysteresis models suggested in the previous research were validated for the dynamic analysis. The results of the shaking table test were compared with the dynamic analysis results using the suggested nonlinear hysteresis models. As a result, the nonlinear hysteresis models were expected to be applicable to the dynamic analysis of URM buildings. Based on the models, the dynamic analysis of domestic URM buildings varying the number of stories and opening ratio was carried out. The analysis results showed that most of the domestic URM buildings were very vulnerable to design earthquake in Korea.

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.150-159
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• 2013

The government has focused on activation of overseas construction projects and strengthening competitiveness in the long term. In recent years Public construction contract as well as design, engineering, construction management(CM) are gradually expanding into other countries, but risk analysis cases in the field are slight. In this study, We utilized PI scale and drew a conclusion about the importance of overseas risk by participants. We compared its features from the risk factor based on Risk Matrix. As a result of this study total of 6 section 31 Country Risk factors for the importance of overseas risk by participants were drawn, and the key risk factors (17 constructor, 14 designers, 17 CMr) based on Risk Matrix were derived. By utilizing the result of this study will be used as the basic data for establishing risk management strategy to meet each business and planning evaluation model.

• Journal of Korean Society on Water Environment
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• v.32 no.2
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• pp.163-172
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• 2016

This study aimed to develop a plan for effective performance of a watershed through correct identification of a river watershed by using the flowrate of the river and water quality data, which is the basis for the establishment of the water environment policy. The target river for water quality improvement was selected based on the monitoring result for 4 water systems in Chungcheongnamdo province in the recent 3 years. The result of analysis for the distribution of discharge capacity by a pollution source group for the water quality improvement target river showed that most of the target river has a high discharge capacity in the water system for living and livestock. Analysis for the density of the total discharge capacity of the whole watershed of Chungcheongnamdo indicated that the river that needs water quality improvement has high BOD concentration and high discharge load density at the point that this river is located. Thus, for efficient watershed management through selection and concentration, Chungcheongnamdo needs to improve the target river in priority. Stepwise planning is also required to establish and execute the water quality improvement in order to satisfy said target water quality, and establish the index for the water improvement rate for its evaluation.

• Communications of Mathematical Education
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• v.35 no.4
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• pp.505-525
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• 2021

In this study, we investigated how multiplication by 2-digit numbers had been taught in elementary mathematics textbooks of Korea, Japan, Singapore, and USA. As a result of analysis, we found as follows. Korean textbooks do not teach the multiplication by 10 and the multiplication by power of 10, but Japanese, Singapore, and US textbooks explicitly teach related content. In the '×tens' teaching, Japanese and American textbooks teach formally the law of association of multiplication applied in the process of calculating the partial product of multiplication. The standard multiplication algorithm generally followed a standard method of recording partial product result according to the law of distribution, but the differences were confirmed in the multiplication model, the teaching method of the law of distribution, and the notation of the last digit '0'. Based upon these results, we suggested some proposals for improving the multiplication teaching.

• Asia-Pacific Journal of Business
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• v.12 no.3
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• pp.281-294
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• 2021

Purpose - The purpose of this study was verifying the policy effects by field of innovative growth engines, focusing on the discussion of the relationship between government support and corporate R&D activities (substitute/complementary goods), and based on the results, policy recommendations for promoting private R&D were carried out. Design/methodology/approach - Through literature research, academic/theoretical discussions about relationship between government support and corporate R&D activities were synthesized. Next, survey data were collected for companies engaged in the field of innovative growth engines and empirical analysis was conducted on the relationship between government support and R&D activities in 13 major sectors. Findings - First, as a result of analyzing all companies regardless of sector, government R&D subsidies had a positive (+) relationship with R&D activities of companies engaged in innovative growth engines, that is, a complementary relationship. Next, as a result of performing empirical analysis by dividing the 13 fields, it was found that 9 fields were complementary goods in which government support had a positive (+) effect on the R&D activities of companies. On the other hand, in the remaining four fields, the effect of government support on corporate R&D activities was not statistically significant. Research implications or Originality - In order to promote R&D activities of companies in the 9 fields where government support acts as a complementary product, it is necessary to establish policies centered on direct government support. On the other hand, it would be more desirable to seek indirect support rather than direct support in the 4 fields where government support did not have a statistically significant effect on corporate R&D activities.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.3
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• pp.29-43
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• 2012

This study evaluated 23 botanic gardens and arboretums under two main categories including professional group and operational group. As for professional group, the main difference between the functions of botanic gardens and arboretums was analyzed. In the case of operational group compared professional group respectively, on categories including importance of function and implementation, seeking to provide fundamental data of botanic gardens and arboretums by enhancing the quality of visitors and examining functional differences. The result of a difference in arboretums' function between professional and operational groups, the study analyzed the importance of botanic gardens and arboretums in terms of detailed categories such as research, education, collection, display, retention, and service for visitors. As a result, professional group showed retention 4.32>education 4.11>research 4.09>service for visitors 4.05, and operational group showed retention 3.70>service 3.52>education 3.41>research 3.37, indicating that both groups had retention as the most selected answer. Looking closely at the functions of the currently implemented detailed categories of botanic gardens and arboretums, such as research, education, collection, display, retention, and service for visitors, the study showed that 91.3% selected rare species and individual multiplication for research function, 78.3% chose education of natural ecosystem for children for education, 73.9% answered space for experiencing nature for display, and 73.9% also replied managon, diof rare species, reproduction, and retention of native plants' species for retention category, and service for visitors showed 95.7% for implementation. The study could not clearly point out the influence between predictors due to absence of an established comprehensive evaluation model. Also, it analyzed and reviewed comparison of functions of professional group and operational group, but in the future, it should conduct study on a systemic and objective classification of botanic gardens and arboretums to clearly examine the difference in views between groups, which also requires, at the same time, study on management policy of botanic gardens and arboretums or suggesting guidelines that suit types of forms, and also study on facilities and program development that can be applied to each class.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.8
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• pp.627-638
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• 2017

Expecting fatigue life of mounted radar in aircraft is very important when designing, because the mounted radar in aircraft is exposed to long-term external random vibration. Among the methods of predicting the fatigue life, Fatigue analysis method in frequency domain has continuously been proposed in this field. In this paper, four fatigue analysis methods in frequency domain, which are widely used, have been selected and compared with the results for Specimen fatigue test. As a result, Dirlik and Benascicutti-Tovo methods have been matched better with fatigue analysis in time domain than the method in frequency method through the comparison between the fatigue analysis method in time domain and the method in frequency domain by conducting the specimen fatigue test with strain gage. Based on the results of the specimen fatigue test, We have conducted fatigue analysis of mounted radar in aircraft with Dirlik and Benasciutti-Tovo methods in the finite element model, and confirmed that the required life was satisfying.