• International conference on construction engineering and project management
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• 2015.10a
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• pp.280-283
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• 2015

Many construction projects have used the building information modeling (BIM) extensively considering data interoperability throughout the projects' lifecycles. However, the current approach, which is to collect the data required to support facility maintenance system (FMS) has a significant shortcoming in that there are various individual pieces of information to represent the performance of the facility and the condition of each of the elements of the facility. Since a heterogeneous external database could be used to manage a construction project, all of the conditions related to the building cannot be included in an integrated BIM-based building model for data exchange. In this paper, we proposed an ontology-based facility maintenance information model to integrate multiple, related pieces of information on the construction project using industry foundation classesbased (IFC-based) BIM data. The proposed process will enable the engineers who are responsible for facility management to use a BIM-based model directly in the FMS-based work process without having to do additional data input. The proposed process can help ensure that the management of FMS information is more accurate and reliable.

• Journal of the Korean housing association
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• v.20 no.3
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• pp.1-10
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• 2009

The final aim of this study was to propose guidelines for the indoor environment of apartment remodeling projects. The first task of this study was to understand the major elements and the actual condition of the remodeling for apartment unit by carrying out in-depth interviews on residents and specialists. The open-access interviews were conducted with interior designers who have a wide experience of apartment remodeling and residents who live in recently remodeled apartment units. The second task was to evaluate the actual condition of the indoor environment and to analyze the main factors that affect the indoor environment in remodeled apartment units. Field measurements were carried out in twenty apartment units occupied after remodeling, recording indoor environment elements (indoor temperature, globe temperature, relative humidity, $CO_2$, CO, PM10, TVOC, HCHO, illumination, and equivalent noise level). Moreover, resident interviews and researcher observations were carried out to determine the contents of the remodeled unit and to investigate the architectural and living factors(like ventilation characteristics, etc.) related to the indoor environment. The results are as follows. The remodeling elements generally included the changing of lighting fixtures and finishing materials in all the spaces, the integration of the balcony into the children's room, the installation of furniture in the kitchen and the entrance, the changing storage furnitures and equipments in the bathroom. The average levels of each unit of relative humidity, $CO_2$, TVOC, HCHO, equivalent noise level, and illumination were proved to be on the whole in inadequate condition. The factors that affect these indoor elements were classified as remodeling factors (remodeling amounts, extent balcony integration, and lighting fixture exchange), ventilation characteristics, and living factors. According to these results, this research proposed the guidelines for the indoor environment in apartment remodeling projects.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.2
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• pp.123-130
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• 2008

The effects of characteristic condition number on the convergence of preconditioned Navier-Stokes equations were investigated. The two-dimensional preconditioned Navier-Stokes adopting Choi and Merkle's preconditioning and the temperature preconditioning are considered. Preconditioned Roe's FDS scheme was adopted for spatial discretization and preconditioned LU-SGS scheme was used for time integration. It is shown that the convergence characteristics of the Navier-Stokes equations are strongly affected by the characteristic condition number. Also it is shown that the optimal characteristic condition numbers for viscous flows are larger than that in inviscid flows.

• Earthquakes and Structures
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• v.9 no.1
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• pp.173-194
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• 2015

Site response analysis is an important topic in earthquake engineering. A time-domain numerical method called as one-dimensional (1D) finite element artificial boundary method is proposed to simulate the homogeneous plane elastic wave propagation in a layered half space subjected to the obliquely incident plane body wave. In this method, an exact artificial boundary condition combining the absorbing boundary condition with the inputting boundary condition is developed to model the wave absorption and input effects of the truncated half space under layer system. The spatially two-dimensional (2D) problem consisting of the layer system with the artificial boundary condition is transformed equivalently into a 1D one along the vertical direction according to Snell's law. The resulting 1D problem is solved by the finite element method with a new explicit time integration algorithm. The 1D finite element artificial boundary method is verified by analyzing two engineering sites in time domain and by comparing with the frequency-domain transfer matrix method with fast Fourier transform.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.271-276
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• 2009

An local area weather condition monitoring system to minimize many disasters from the sudden change of weather condition in local and mountain area is proposed. Firstly, the comparison of present state of the related monitoring systems and the possibility of realization with some merits are investigated. Moreover, this paper present direction of local area weather condition monitoring system based on integration of wireless sensor network and CDMA network following some case study. Through the efficient integration of both networks, the measured weather condition data from sensors can be transmitted to the server or mobile to monitor with high reliability. The proposed monitoring system will guide new type of project in wireless sensor network and support alarm service of the sudden change of weather condition to mobile user from central official regulations.

• Science of Emotion and Sensibility
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• v.13 no.3
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• pp.475-484
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• 2010

This study examined the influence of the SOA(stimulus onset asynchrony) between visual and auditory stimuli on the integration phenomenon of audio-visual senses. Within the stimulus integration phenomenon, the redundant target effect (the faster and more accurate response to the target stimulus when the target stimulus is presented with more than two modalities) and the visual dominance effect (the faster and more accurate response to a visual stimulus compared to an auditory stimulus) were examined as we composed a visual and auditory unimodal target condition and a multimodal target condition and then observed the response time and accuracy. Consequently, despite the change between visual and auditory stimuli SOA, there was no redundant target effect present. The auditory dominance effect appeared when the SOA between the two stimuli was over 100ms. Theses results imply that the redundant target effect is continuously maintained even when the SOA between two modal stimuli is altered, and also suggests that the behavioral results of superior information processing can only be deducted when the time difference between the onset of the auditory stimuli and the visual stimuli is approximately over 100ms.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.69-78
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• 2005

ARCO and TAO data which supply three dimensional global ocean information are assimilated to the background field from a general circulation model, MOM3. Using a variational Analysis using Filter (VAF), which is a spatial variational filter designed to reduce computational time and space efficiently and economically, observed ARGO and TAO data are assimilated to the OGCM-generated background sea temperature for the generation of initial condition of the model. For the assessment of the assimilation impact, a comparative experiment has been done by integrating the model from different intial conditions: one from ARGO-, TAO-data assimilated initial condition and the other from background state without assimilation. The assimilated analysis field not only depicts major oceanic features more realistically but also reduces several systematic model bias that appear in every current OGCMs experiments. From the 10-month of model integrations with and without assimilated initial conditions, it is found that the major assimilated characteristics in sea temperature appeared in the initial field remain persistently throughout the integration. Such implies that the assimilated characteristics of the reduced sea temperature bias is to last in the integration without rapid restoration to the non-assimilated OGCM integration state by dispersing mass field in the form of internal gravity waves. From our analysis, it is concluded that the data assimilation method adapted in this study to MOM3 is reasonable and applicable with dynamical consistency. The success in generating initial condition with ARGO and TAO data assimilation has significant implication upon the prediction of the long-term climate and weather using ocean-atmosphere coupled model.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.55-58
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• 2005

The present study aims to design electrically and structurally effective antenna structures in order that the structural surface itself could become the antenna. The basic design concept is composite sandwich structure in which microstrip antenna is embedded and this is termed composite smart structure (CSS). The most important outstanding problem is that composite materials of structural function cannot be used without reducing antenna efficiency. Unfortunately, such materials have high electrical loss. This is a significant design problem that needs to be solved in practical applications. Therefore, the effects of composites facesheet on antenna performances are investigated in the first stage and changes in the gain of microstrip antenna due to composites facesheet have been determined. ‘Open condition’ is defined when gain is maximized and is a significant new concept for the design of high-gain antennas considering bandwidth in practical application. The open condition can be made with the outer facesheet by controlling its position. In the design of CSS, glass/epoxy composites and Nomex honeycomb were used with exploiting open condition. Experiments, confirm that the gain is improved and the bandwidth is also as wide as specified in our requirements. With the open condition, wideband antenna can be integrated with mechanical structures without reducing any electrical performances, as confirmed experimentally here.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2116-2121
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• 2008

Removal of particles at rich $CO_2$ condition has been important in the gas cleaning for $CO_2$ capture in Oxy-fuel combustion. Electrostatic precipitators (ESPs) have been widely used to remove particles in exhaust gases from present air combustion. However, few studies on characteristics of ESPs under a $CO_2$ rich gas condition have been conducted. In this study, we investigated integration of electrostatic precipitators (ESP) for removing submicron particles along with corona discharge characteristics and collection efficiency of submicron particles at $CO_2$ rich condition. The overall performance of ESP is represented by collection efficiency as function of energy consumption. The experiment results showed that higher the concentration of $CO_2$ gas, the corona discharge currents were lower at the same applied voltages and the spark over occurred at lower voltages, and the collection efficiency of submicron particles under 50, 80% $CO_2$ conditions was much lower than that under 100% Air.

• Journal of the Earthquake Engineering Society of Korea
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• v.25 no.6
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• pp.283-292
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• 2021

In this study, a structural health monitoring system for cable-stayed bridges is developed. In the system, condition assessment of the structure is performed based on measured records from seismic accelerometers. Response indices are defined to monitor structural safety and serviceability and derived from the measured acceleration data. The derivation process of the indices is structured to follow the transformation from the raw data to the outcome. The process includes noise filtering, baseline correction, numerical integration, and calculation of relative differences. The system is packed as a condition assessment program, which consists of four major processes of the structural health evaluation: (i) format conversion of the raw data, (ii) noise filtering, (iii) generation of response indices, and (iv) condition evaluation. An example set of limit states is presented to evaluate the structural condition of the test-bed and cable-stayed bridge.