• Korean Journal of Construction Engineering and Management
• /
• v.10 no.2
• /
• pp.145-154
• /
• 2009

For developing an Automation equipment in construction, it is a key issue to develop 3D modeling technology which can be used for automatically recognizing environmental objects. Recently, for the development of "Intelligent Excavating System(IES), a research developing the real-time 3D terrain modeling technology has been implemented from 2006 in Korea and a stereo vision system is selected as the optimum technology. However, as a result of performance tests implemented in various earth moving environment, the 3D images obtained by stereo vision included considerable noise. Therefore, in this study, for getting rid of the noise which is necessarily generated in stereo image matching, the noise elimination algorithm of stereo-vision images for 3D terrain modeling was developed. The consequence of this study is expected to be applicable in developing an automation equipments which are used in field environment.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.20 no.6
• /
• pp.76-82
• /
• 2016

Recently, environmental sustainability of the transitional explosives and propellants is an issue of growing importance in energetic materials. For examples, ammonium perchlorate(AP) as an solid propellants oxidizer could create a poisonous gas and atmospheric pollutions, such as HCl. Among the several oxidizers, hydrazinium nitroformate(HNF) is an effective candidate substance for eco-friendly oxidizer, which has high density, pressure index, and less smog generating property during combustion for the thrust control system. This study was controlled the size distribution and shapes through various conditions. Length and diameter ratio(L/D) of crystals has below 1 : 3, and the particle size was two types of $200{\mu}m$ and $50{\mu}m$.

• Coupled systems mechanics
• /
• v.4 no.1
• /
• pp.37-65
• /
• 2015

Modeling and simulation of mechanical response of infrastructure object, solids and structures, relies on the use of computational models to foretell the state of a physical system under conditions for which such computational model has not been validated. Verification and Validation (V&V) procedures are the primary means of assessing accuracy, building confidence and credibility in modeling and computational simulations of behavior of those infrastructure objects. Validation is the process of determining a degree to which a model is an accurate representation of the real world from the perspective of the intended uses of the model. It is mainly a physics issue and provides evidence that the correct model is solved (Oberkampf et al. 2002). Our primary interest is in modeling and simulating behavior of porous particulate media that is fully saturated with pore fluid, including cyclic mobility and liquefaction. Fully saturated soils undergoing dynamic shaking fall in this category. Verification modeling and simulation of fully saturated porous soils is addressed in more detail by (Tasiopoulou et al. 2014), and in this paper we address validation. A set of centrifuge experiments is used for this purpose. Discussion is provided assessing the effects of scaling laws on centrifuge experiments and their influence on the validation. Available validation test are reviewed in view of first and second order phenomena and their importance to validation. For example, dynamics behavior of the system, following the dynamic time, and dissipation of the pore fluid pressures, following diffusion time, are not happening in the same time scale and those discrepancies are discussed. Laboratory tests, performed on soil that is used in centrifuge experiments, were used to calibrate material models that are then used in a validation process. Number of physical and numerical examples are used for validation and to illustrate presented discussion. In particular, it is shown that for the most part, numerical prediction of behavior, using laboratory test data to calibrate soil material model, prior to centrifuge experiments, can be validated using scaled tests. There are, of course, discrepancies, sources of which are analyzed and discussed.

• Nuclear Engineering and Technology
• /
• v.48 no.5
• /
• pp.1237-1251
• /
• 2016

Although the horizontal component of an earthquake response can be significantly reduced through the use of conventional seismic isolators, the vertical component of excitation is still transmitted directly into the structure. Records from instrumented structures, and some recent tests and analyses have actually seen increases in vertical responses in base isolated structures under the combined effects of horizontal and vertical ground motions. This issue becomes a great concern to facilities such as a Nuclear Power Plants (NPP), with specialized equipment and machinery that is not only expensive, but critical to safe operation. As such, there is considerable interest worldwide in vertical and three-dimensional (3D) isolation systems. This paper examines several vertical and 3D isolation systems that have been proposed and their potential application to modern nuclear facilities. In particular, a series of case study analyses of a modern NPP model are performed to examine the benefits and challenges associated with 3D isolation compared with horizontal isolation. It was found that compared with the general horizontal isolators, isolators that have vertical frequencies of no more than 3 Hz can effectively reduce the vertical in-structure responses for the studied NPP model. Among the studied cases, the case that has a vertical isolation frequency of 3 Hz is the one that can keep the horizontal period of the isolators as the first period while having the most flexible vertical isolator properties. When the vertical frequency of isolators reduces to 1 Hz, the rocking effect is obvious and rocking restraining devices are necessary.

• Journal of Korean Society of Disaster and Security
• /
• v.13 no.3
• /
• pp.15-28
• /
• 2020

Hydrological data is very important in understanding the hydrological process and identifying its characteristics to protect human life and property from natural disasters. In particular, hydrological analysis are often performed assuming that hydrological data are stationary. However, recently climate change has raised the issue of climate stationary, and it is necessary to analyze the nonstationary of the climate. In this study, a method to analyze the stationarity of hydrological data was examined using the annual precipitation of 37 meteorological stations with long - term record data. Therefore, in this study, the stationary was determined by analyzing the persistence, trend, and stability using annual precipitation. Overall results showed that a trend was observed in 4 out of 37 stations, stable was investigated at 15 stations, and persistence was shown at 4 stations. In the stationary analysis using the annual precipitation data, 25 stations (67% of 37 stations) were nonstationary.

• Smart Media Journal
• /
• v.1 no.4
• /
• pp.52-58
• /
• 2012

In recent years the combination of IT and BT for U-Healthcare Medical Services has attracted popular attention as an alternative for solving health problems due to aging issue. Active oxygen as free radicals causes unstable state of the body resulting to other disease on which approximate 90% of the diseases are associated with active oxygen. The severity is even higher along with increasing age. Therefore, there is a need for systematic management of active oxygen saturation for the elderly and chronic patients. In this paper, the data about active oxygen measurements from the body measurement is sent to the data storage of medical facilities by the service provider. Medical information is measured by devices provided complying with the standard, support and information using Bluetooth communication. Users can check their health status themselves using the proposed system through 3G/4G mobile devices like smart phone to medical institutions in which the smart phone act as a gateway for medical data transferred from patient to medical institutions and vice versa. Users can get and experience a diagnosis and effective U-Environmental Health Services from Medical institutions anywhere using the proposed built system.

• Advances in Traditional Medicine
• /
• v.10 no.3
• /
• pp.141-149
• /
• 2010

A concern of safety issue for traditional herbal medicine is the possibility of some herbs containing heavy metals responsible for several cases of metal poisoning. In our previous study, the physiological levels of heavy metals, such as Cd, Cu, Hg and Pb, were examined to evaluate a potential risk in patients taking herbal medicine. In this study, the levels of 12 heavy metals, including non-metallic element, Se, were analyzed in hair and compared to the results from the previous study. In the previous study, the levels of Cd, Cu, Hg and Pb in hair showed a significantly lower odds ratio than 1. In this study, however, all metals did not show any significant odds ratio higher or lower than 1 even if 5 of 12 metals showed lower odds ratio than 1. In addition, the levels of metal concentrations, especially for Cu, Fe, Pb and Zn, exceeding the WHO reference values were observed in hair. However, any evidence for metal accumulation in hair caused by taking herbal medicines for long duration was not observed in analysis of multiple regression and odds ratio from case-control study. This result would show another possibility for a role of herbs as a non-enzymatic chelator inhibiting the gastrointestinal absorption of heavy metals.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.6
• /
• pp.1925-1935
• /
• 2014

Initiatives for balanced growth are centered on urban centers and strictly based upon focused areas and quantitative economics, and thus have rather facilitated the urbanization while deteriorating rural areas' competitiveness. Although huge supports have been made by the central government to address this issue, the effects are very low, due to the limitation of top-down approaches. Recently, however, the demand of differentiated policies for rural communities increases while the necessity of diagnostic index tailored for individual municipalities is also highlighted. The present study investigates diagnostic indices discussed in the preceding studies and derives optimum ones suitable for rural area evaluation. To this end, an index pool was constructed and a set of indices was developed through experts interview and factor analysis. It is expected that the indices help planners effectively diagnose rural areas, and contribute to expand the applicability of 'Customized Diagnostic Technologies.'

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.37 no.4
• /
• pp.759-764
• /
• 2017

The paper is intended to explore the spatial relations between flooded buildings and urban expansion phenomena by employing urban expansion intensity index and hotspot analysis methods for the case of Gangneung. Two major results are as followed; first, flooding susceptible areas are found in the regions where the highly intense development occurs within a short period of time, so called pseudo-urbanization. Second, less flooded buildings exist in old towns where it is believed that there is the lack of urban infrastructure services. This study indicates the possibility that the highly intense development and pseudo-urbanization with a relatively short time period relate to flooded building events. In addition, the possibility leads to another issue that new developments might be increasing the flooding vulnerability worse than before, particularly, to the adjacent old towns. For the better understanding, it is desirable to have further related case studies in the near future.

• The Bulletin of The Korean Astronomical Society
• /
• v.38 no.1
• /
• pp.40.2-40.2
• /
• 2013

The properties of bright galaxies are closely related to those of their nearby neighbors and satellite galaxies. In addition, the properties of galaxies in clusters are known to be strongly affected by the cluster environment. These two environmental effects raise a question: how significantly do nearby neighbors and satellite galaxies affect the properties of bright galaxies in a cluster? To address this issue, we reduce and analyze the deep and wide-field images of Abell 3659 (z ~ 0.0907) in the g' and r' bands obtained using IMACS on the Magellan (Baade) 6.5m telescope. The main goal of this study is to find out the relationship between the properties of bright galaxies and those of fainter companion galaxies in a cluster. This poster is a progress report, in which we present the sample selection and the preliminary results.