• Steel and Composite Structures
• /
• v.41 no.5
• /
• pp.761-773
• /
• 2021

This study presents a 3D non-linear finite element (FE) assessment of dynamic soil-structure interaction (SSI). The numerical investigation has been performed on the time domain through a Finite Element (FE) system, while considering the nonlinear behavior of soil and the multi-directional nature of genuine seismic events. Later, the FE outcomes are analyzed to the recorded in-situ free-field and structural movements, emphasizing the numerical model's great result in duplicating the observed response. In this work, the soil response is simulated using an isotropic hardening elastic-plastic hysteretic model utilizing HSsmall. It is feasible to define the non-linear cycle response from small to large strain amplitudes through this model as well as for the shift in beginning stiffness with depth that happens during cyclic loading. One of the most difficult and unexpected tasks in resolving soil-structure interaction concerns is picking an appropriate ground motion predicted across an earthquake or assessing the geometrical abnormalities in the soil waves. Furthermore, an artificial neural network (ANN) has been utilized to properly forecast the non-linear behavior of soil and its multi-directional character, which demonstrated the accuracy of the ANN based on the RMSE and R² values. The total result of this research demonstrates that complicated dynamic soil-structure interaction processes may be addressed directly by passing the significant simplifications of well-established substructure techniques.

• Economic and Environmental Geology
• /
• v.39 no.6 s.181
• /
• pp.711-717
• /
• 2006

In order to study gas hydrate, potential future energy resources, Korea Institute of Geoscience and Mineral Resources has conducted seismic reflection survey in the East Sea since 1997. one of evidence for presence of gas hydrate in seismic reflection data is a bottom simulating reflector (BSR). The BSR occurs at the interface between overlaying higher velocity, hydrate-bearing sediment and underlying lower velocity, free gas-bearing sediment. That is often characterized by large reflection coefficient and reflection polarity reverse to that of seafloor reflection. In order to apply depth migration to seismic reflection data. we need high performance computers and a parallelizing technique because of huge data volume and computation. Phase shift plus interpolation (PSPI) is a useful method for migration due to less computing time and computational efficiency. PSPI is intrinsically parallelizing characteristic in the frequency domain. We conducted conventional data processing for the gas hydrate data of the Ease Sea and then applied prestack depth migration using message-passing-interface PSPI (MPI_PSPI) that was parallelized by MPI local-area-multi-computer (MPI_LAM). Velocity model was made using the stack velocities after we had picked horizons on the stack image with in-house processing tool, Geobit. We could find the BSRs on the migrated stack section were about at SP 3555-4162 and two way travel time around 2,950 ms in time domain. In depth domain such BSRs appear at 6-17 km distance and 2.1 km depth from the seafloor. Since energy concentrated subsurface was well imaged we have to choose acquisition parameters suited for transmitting seismic energy to target area.

• Radiation Oncology Journal
• /
• v.9 no.2
• /
• pp.343-350
• /
• 1991

The quasi-conformation therapy was performed to get a homogeneous dose distributions for irregeular shaped tumor lesion by using the arc moving beam and beam modifying filter which was made by cerrobend alloy($\rho$=9.4 g/cc) metal. In our dose calcuation programme, it was fundmentally based on Clarkson's method to calcuate the irregular multi-step block field in rotation therapy. In this study, the expected relative depth doses under multipartial attenuator agree well with measured data at same plane. The results of comparison the dose computation with that of TLD measurement are very closed within ${\pm}5\%$ uncertainties in the irradiation to phantom with quasi-comformation method. And it has shown that irregular typed multi-step filter can be applied to quasi-conformation therapy in high energy radiation plannings.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.28 no.4
• /
• pp.222-231
• /
• 2016

Multi-member lattice-type structures including jackets and tripods are being considered as good alternatives to monopile foundations for relatively deep water of 25-50 m of water depth owing to their technical and economic feasibility. In this study, the reliability analysis of bottom-fixed offshore wind turbines with monopile and/or multi-member lattice-type foundations is carried out and the sensitivities of random variables such as material properties, external wind loadings and scouring depth are compared with respect to different types of foundations. Numerical analysis of the NREL 5 MW wind turbine supported by monopile, tripod and jacket substructures shows that the uncertainties of soil properties affect the reliability index more significantly for the monopile-supported OWTs while the reliability index is not so sensitive to the material properties in the cases of tripod- and jacket-supported OWTs. In conclusion, the reliability analysis can be preliminarily carried out without considering soil-pile-interaction in the cases of tripod- and jacket-supported OWTs while it is very important to use the well-measured soil properties for reliable design of monopile-supported OWTs.

• Journal of the Economic Geographical Society of Korea
• /
• v.21 no.1
• /
• pp.53-68
• /
• 2018

Community-based ecotourism (CBE), if well-developed can be a practical approach for promoting socio-economic well-being and sustaining ecological resources. The growth and its development worldwide especially in developing economies is a welcome development. The study aimed at assessing the Boabeng-Fiema Monkey Sanctuary in Ghana, as an example of traditional conservation system of management that has ensured greater community participation, equity, inclusiveness, and multi-level stakeholder partnership. In-depth interviews with key informants and documentary analysis of relevant peer reviewed and grey literature were the main qualitative data collection used. Results revealed that majority of the interviewees support and value the current system of traditional management. The enforcement of rules and regulations and other cultural and religious practices were discussed by key informants. Opportunities for multiple livelihood strategies as a result of the CBE is seen as critical for increasing local's acceptance and participation. The remarkable growth of the sanctuary, as well as the increase in human population, has created a shortage of land for domestic and other commercial purposes which is identified as posing a major challenge to the sustenance of the sanctuary. The study recommends diversification of livelihood opportunities presented by the presence of the sanctuary like the introduction of homestay concept, craft making- wood carving, painting, artisan shops.

• Journal of Ocean Engineering and Technology
• /
• v.31 no.1
• /
• pp.69-79
• /
• 2017

This paper presents the operations of a multi-beam echo sounder (MBES) installed on the deep-sea remotely operated vehicle (ROV) Hemire. Hemire explored hydrothermal vents in the Forecast volcano located near the Mariana Trench in March of in 2006. During these explorations, we acquired profiling points on the routes of the vehicle using the MBES. Information on the position, depth, and attitude of the ROV are essential to obtain higher accuracy for the profiling quality. However, the MBES installed on Hemire does not have its own position and depth sensors. Although it has attitude sensors for roll, pitch, and heading, the specifications of these sensors were not clear. Therefore, we had to merge the high-performance sensor data for the motion and position obtained from Hemire into the profiling data of the MBES. Then, we could properly convert the profiling points with respect to the Earth-fixed coordinates. This paper describes the integration of the MBES with Hemire, as well as the coordinate conversion between them. Bathymetric maps near the summit of the Forecast volcano were successfully collected through these processes. A comparison between the bathymetric maps from the MBES and those from the Onnuri Research Vessel, the mother ship of the ROV Hemire for these explorations, is also presented.

• Journal of Korea Water Resources Association
• /
• v.39 no.1 s.162
• /
• pp.1-9
• /
• 2006

Recently, the flood damages including losses of human lifes and property have been rapidly increased according to extreme floods. And we know that the flood control project is needed for diminishing flood damages. However, we have had the lacks in a reasonable methodology for the economic analysis of food control project. This study aims to improve the existing economic analysis method for flood control project. So, first of all, we understand the problems of existing economic analysis and investigate the methodologies of foreign countries. Based on that, the Multi-Dimensional Flood Damage Analysis(MD-FDA) is developed in this study. The survey of properties on the floodplain is conducted, then the damage rate obtained by evaluating the monetary values of surveyed property is applied, and the expected flood damage is calculated. Also by considering damage area in the floodplain as well as spatial distribution of inundated depth using GIS, the flood damages are evaluated more accurately than existing method. From the study, we know that the MD-FDA can improve the problems of existing method and evaluate the reasonable flood damages by using updated nation리 statistics.

• Journal of The Korea Institute of Healthcare Architecture
• /
• v.18 no.3
• /
• pp.41-49
• /
• 2012

Most large-sized and tall-risen general hospitals of today fairly depend on in-patient wards in designing hospital styles. The core planning for the efficient movements of various people in the words should take into account the sustainable connections between/among the floors, as well as hospital structures and mechanical functions. This study sampled for the study 19 hospital in-patient wards and investigated their flat-core styles. It was found out that hospital structures are changing from symmetrical styles of triangles, quadrangles and rectangles through bending, configuring, transforming to efficient new styles. Symmetrically quadrangled flat-styles are made of multi-cores spread with main an sub-cores. In contrast, symmetrically triangled flat-styles place the open place in the middle in order to prevent from its deepening, and widened the depth line through changing the outdoor top point. Non-symmetrical rectangles minimized the depth value to maintain the recent styles used in the wards, and tended to prefer the transformed styles of quadrangles. The double-corridors easily transshaped from mono corridors reveals the triangled, W-shaped, or Y-shaped figures. The site area ratio of the cores is 11.95% in average. The number of beds which one elevator covers is 66.51 beds in average, and the size of site area which one elevator covers 216.68m. Most cores on the base floor clustered around the average value, with more than 1000 beds shoes 12.83%, does 12.93%, does 14.64%, does 14.58%, which says that the core ratio increases according to hospital beds.

• Geotechnical Engineering
• /
• v.1 no.1
• /
• pp.5-12
• /
• 1985

Ocassionally it is used for simple extensions of Terzahgi's theory to account for time-depend- tint loading but there is little evidence of application in more complicated consolidation theories that take into account such effects as nonlinear stress.strain, layered systems or large strains. The purpose of this paper provides an efficient computer algorthm based on numerical analysis using finite difference method which account for multi-layered soils to determine the degree of consolidation and excess pore pressures relative to time and positions more realistically. The explicitly scheme of solving the consolidation equations has been investigated from the point of view of the stability conditions and the convergence with variance of the operator as well as to obtain an optimal divided depth ratios of total depth. A comparison of the settlement predictions with both the classical analysis and the algorithm based on numerical analysis indicates that the new algorithm scheme is found to be superior to the classical theory in the layered soils.

• Journal of The Korean Astronomical Society
• /
• v.54 no.2
• /
• pp.37-47
• /
• 2021

Reverberation mapping (RM) is an efficient method to investigate the physical sizes of the broad line region (BLR) and dusty torus in an active galactic nucleus (AGN). The Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) mission will provide multi-epoch spectroscopic data at optical and near-infrared wavelengths. These data can be used for RM experiments with bright AGNs. We present results of a feasibility test using SPHEREx data in the SPHEREx deep regions for torus RM measurements. We investigate the physical properties of bright AGNs in the SPHEREx deep field. Based on this information, we compute the efficiency of detecting torus time lags in simulated light curves. We demonstrate that, in combination with complementary optical data with a depth of ~ 20 mag in B-band, lags of ≤ 750 days for tori can be measured for more than ~ 200 bright AGNs. If high signal-to-noise ratio photometric data with a depth of ~ 21-22 mag are available, RM measurements are possible for up to ~ 900 objects. When complemented by well-designed early optical observations, SPHEREx can provide a unique dataset for studies of the physical properties of dusty tori in bright AGNs.