• Smart Structures and Systems
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• v.30 no.5
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• pp.447-462
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• 2022

The viscosity of a shear-thickening fluid damper (STFD) can increase dramatically when the STFD undergoes high-rate of excitation. Therefore, accurate numerical modelling of the STFD has been considered difficult due to this distinct feature. This study aims to develop a numerical model to accurately simulate the response of the STFD. First, a STFD is designed, fabricated, and installed in the laboratory. Then, performance tests are conducted in which sine waves with nine frequencies at three amplitude levels are adopted as the displacement excitations to the STFD. A novel numerical model which contains two parameter sets of the discrete Bouc-Wen model as well as two parameters for transiting the two parameter sets. Therefore, a total number of eighteen parameters need to be identified in the damper model. The symbiotic organisms search is applied to optimize the parameters. Numerical simulation results demonstrate that the proposed STFD model with transit parameter sets outperforms the conventional discrete Bouc-Wen model. The proposed STFD model can be applied to analyses of structures in which STFDs are installed in the future.

• Journal of Urban Science
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• v.12 no.2
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• pp.43-52
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• 2023

UAV have the disadvantage that are weak from rainfall or winds due to the light platform, so use Scale-Invariant Feature Transform (SIFT) method which extrude keypoints in image matching process. To find the efficient filtering method for the construction of precise Digital Terrain Model (DTM) using UAV images, comparatively analyzed sobel and Differential of Gaussian (DoG) and found sobel is more efficient way to extrude buildings, trees, and so on. And edges are extruded more clearly when applying median additionally which have the merit of preserving edge and eliminating noise. In this study, applied sobel-median filtering which plus median to sobel and constructed the 1st filtered DTM that extrude building and trees and 2nd filtered DTM that extrude cars by threshold of gradient, Analysis of the degree of accuracy improvement showed that standard deviations of 1st filtered DTM and 2nd filtered DTM are 0.32m, 0.287m respectively, and both are acceptable for the tolerance of 0.33m for elevation points of 1/1,000 digital map, and the accuracy was increased about 10% by filtering automobiles. Plus, moving things are changed those position and direction in every image, and these are not target to filter because of the characteristic that is excluded from SIFT method.

• Structural Monitoring and Maintenance
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• v.11 no.3
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• pp.203-217
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• 2024

Electro-mechanical impedance (EMI) technique is a low-cost structural damage detection method. It reflects structural damage through the change in admittance signal which contains the structural mechanical impedance information. The ambient temperature greatly affects the admittance signal, which hides the changes caused by structural damage and reduces the accuracy of damage identification. This study introduces a convolutional neural network to compensate for the temperature effect. The proposed method uses a framework that consists of a feature extraction network and a decoding network, and the original admittance signal with temperature information is used as the input. The output admittance signal is eliminated from the temperature effect, improving damage identification robustness. The admittance data simulated by the finite element model of the spatial grid structure is used to verify the effectiveness of the proposed method. The results show that the proposed method has advantages in identification accuracy compared with the damage index minimization method and the principal component analysis method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.157-167
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• 2006

During the first and second NGIS projects by the Korean government, The first one (1995~2000) was limited on constructing geographic information and the second (2001~2005) was focused on circulation and practical use of geoinformation from the result of the first project. In the latter half of 2nd NGIS project, However, the geographic information from the NGIS projects have not been renewed even though there were significant geographical changes. The accurate renewal of geoinformation is a matter of great importance to the next generation industry (e.g. LBS, Ubiquitous, Telematics). In this respect, it is time to update the geographic information in the latter half of the second NGIS project. Therefore, It is not only important to build an accurate geoinformation but also rapid and correct renewal of the geoinformation. NGII (National Geographic Information Institute) has been studying for improvement of digital map that was constructed by the result of the 1st NGIS project. Through the construction of clean digital map, NGII constructed Framework Data to three kinds of formats (NGI, NDA, NRL). Framework Data was contained to other database, and provided the reference system of location or contents for combining geoinformation. Framework Data is consist of Data Set, Data Model and UFID (Unique Feature Identifier). It will be achieved as national infrastructure data. This paper attempts to explore a method of the update to practical framework data with realtime geoinformation on feature's creation, modification and destruction managed by 'Feature management agency' using UFID's process. Furthermore, it suggests a method which can provide important data in order to plan the Framework update with the land change ratio.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.3-12
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• 2011

Technology based civilization has made a sustained advancement, resulting in economic growth and material prosperity. The outcome was the beginning of environmental destruction. Especially, in regard to construction, it has been recognized as a key culprit for pollution. As such, the construction industry has recently shown interest in the environment, as it has been applying environment friendly method of construction and reducing wastes. As the number of old common housing increases in our country, reconstruction and remodeling are implemented as a means of improvement. However, it can be said that remodeling is the inevitable option because of cost and environmental problems associated with reconstruction. As part of its feature, remodeling work is preceded by removal work. And, removal work inevitably creates construction wastes. Treatment of wastes that takes into consideration environmental aspects is important and for this, removal work that is based on environment friendly remodeling to ensure selective separation must be implemented. Yet, a removal work based on environment friendly remodeling has a lower level of output compared to existing methods. Because remodeling work by its nature has a post construction work which proceeds after it, securing work efficiency is important as the removal work is a critical path activity. Thus, the present study improves the work process of a removal work that is based on environment friendly remodeling so that it becomes a work process that includes work efficiency. For this, as a case study, old common housing has been selected, and a TACT process has been developed which is based on data acquired from environment friendly removal work. And, this study develops an optimal TACT process which is based on environment friendly remodeling by conducting a simulation for a 15 floor apartment.

• Journal of the Korean Institute of Landscape Architecture
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• v.35 no.2 s.121
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• pp.25-36
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• 2007

This case study offers fundamental data for the research and construction of future of water. It also provides an understanding of the design and characteristics of the existing water bodies in urban parks. This study was begun by conducting field research on the completion of the construction of 67 different urban parks located in the downtown areas of the following cities: Gimhae, Yangsan, Changwon, Masan, and Jinju. The field research was conducted from July to October of 2006. Additional research was performed in July of 2007. Construction trends were examined and the design and characteristics of the types of locations, shapes, scales, materials, and added objects for the enhancement of recreational value of the 31 water bodies constructed in 18 urban parks out of the 67 were analyzed. According to the results of the study, the most common design feature was a fountain that shot up. The bodies of water were designed by using a simple technique in accordance with the basic principles of location, shape, size, materials, and added objects for the enhancement of recreational value, with the exception of a few different factors in the research subjects. In conclusion, it can be recommended that further research be conducted in the consideration and various plans of location, shape, size, materials, and added objects for the enhancement of recreational value of future constructions of water bodies in urban parks in order to offer a more pleasant environment to the users.

• Korean journal of communication and information
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• v.50
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• pp.73-93
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• 2010

This study examines the characteristics of Korean journalism ethics as job ideology by analyzing the specific conditions revealed in the historical process of the construction of Korean journalism ethics, focusing on the change of social relationships which intervene in the construction of journalism ethics. By this interpretation, this study proposes the desirable directions in journalism ethics discussion and practice strategies in the journalism field. Therefore this study analyzed the historical process and the development phase of discourse in journalism ethics in which the job position of Korean journalists have changed. In result, this study found that the discourse of Korean was used for the instrumental and rhetorical means to cope with the outside pressure in the lack of occupational self-control which becomes the premise of ethics. Because of this, the Korean journalism ethics characterize the rhetorical feature of ethical code, the structured separation of practice from cognition, the conceptual confusion of responsibility from ethics.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.3
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• pp.230-240
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• 2009

The ESCORT model is applied at Mokpo coastal zone to analyze the effect of fresh water discharge released from the gates of the Youngsan River sea-dyke. Applicability and validity of both 2-D and 3-D hydrodynamic modules could be guaranteed by simulating hydrodynamic feature with ebb dominance characteristics. Then, effects of the released discharge on the hydrodynamics are investigated. And analysis of the effects on diffusion phenomena show that 3-D model is essential for such diffusion modelling. Moreover, vertical salinity distributions near the gates are examined, and the influence range of fresh water is also estimated, which shows that dilution of fresh water is going on slowly because of poor flushing.

• Journal of the Society of Disaster Information
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• v.10 no.2
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• pp.320-334
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• 2014

The government policy had placed new construction as the kernel of the investment in the road department. This had been shifted, however, since the government's budget of the road department reached its peak in 2000, new construction had came to a downsizing phase while the maintenance increased gradually. Considering this recent trend, the necessity of a new paradigm in the road policy had came to a fore, in order to prove the justification of increase in the maintenance budget as well as successfully fulfill the user's needs in the service quality. The developed countries that had intensively constructed social infrastructure in 1950-60s are enjoying a great achievement by applying the asset management concept in coping with the deterioration of the public facilities. This research suggests the basic framework in establishing "Korean Road Asset Management System" designed to efficiently manage the national road. The main feature of this system is to absorb economic analysis course into the current pavement management system, in order to form not only long-lasting but also preventive road management policy.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.11
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• pp.1505-1511
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• 2021

Pretrained models with high performance in various tasks within natural language processing have the advantage of learning the linguistic patterns of sentences using large corpus during the training, allowing each token in the input sentence to be represented with appropriate feature vectors. One of the methods of constructing a corpus required for a pre-trained model training is a collection method using web crawler. However, sentences that exist on web may contain unnecessary words in some or all of the sentences because they have various patterns. In this paper, we propose a dataset construction method for filtering sentences containing unnecessary words using neural network models for corpus collected from the web. As a result, we construct a dataset containing a total of 2,330 sentences. We also evaluated the performance of neural network models on the constructed dataset, and the BERT model showed the highest performance with an accuracy of 93.75%.