• Journal of Korean Society for Geospatial Information Science
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• v.19 no.3
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• pp.23-32
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• 2011

This research uses a distributed model, Vflo which can devide subwater shed into square grids and interpret diverse topographic elements which are obtained through GIS processing. To use the distributed model, soil wetness information was extracted through Tasseled Cap transformation from LANDSAT 7 $ETM^+$ satellite data and then they were applied to each cell of the test area, unlike previous studies in which have applied average soil condition of river basin uniformly regardless of space-difference in subwater shed. As a resut of the research, it was ascertained the spatial change of soil wetness is suited to the distributed model in a subwater shed. In addition, we derived out a relation between soil wetness of image collection time and 10 days-preceded rainfall and improved the feasibility of weights obtained by the relation equation.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.159-174
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• 2017

The long-term imbalances between supply and demand in office market can weaken urban growth since excessive supply of offices led to office market instability and excessive demand of offices weakens growth of urban industry. Recently, there have been a lot of new large-scale supplies, which increased volatility in Seoul office market. Nevertheless, new supply of Seoul office has not been fully examined. Given this, the focus of this article was on confirming the influences of profitability, replacement cost, and demand on new office supplies in Seoul. In examining those influences, another focus was on their relative influences over time. For these purposes, we analyzed quarterly data of Seoul office market between 2003 and 2015 using a vector error correction model (VECM). As a result, in terms of the influences on the current new supply, the impact of supply before the first quarter was negative, while that of office employment before the first quarter was positive. Also, that of interest rate before the second quarter was positive, while those of cap rate before the first quarter and cap rate before the second quarter were negative. Based on the findings, it is suggested that prediction models on Seoul offices need to be developed considering the influences of profitability, replacement cost, and demand on new office supplies in Seoul.

• Tribology and Lubricants
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• v.27 no.4
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• pp.198-203
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• 2011

The purpose of this paper is to find a proper cooling system of bearing unit in the submersible motor pump to extend a life time. To do this, heat transfer analysis of the submersible motor pump were performed using commercial CFD code ANSYS. In order to obtain the resonable heat transfer simulation results, we first set up mathematical model of heat source in the bearing system, and carried out heat transfer analysis with the model. As a results, new type bearing cap which had several ribs for cooling the bearing was proposed. Finally, through the comparison between experimental results of old and new model pump, we proofed that maximum bearing temperature of new model was about 10% lower than that of old model.

• Advances in concrete construction
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• v.10 no.1
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• pp.49-59
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• 2020

Precast concrete elements in accelerated bridge construction (ABC) extends from superstructure to substructure, precast pile foundation has proven a benefit for regions with fragile ecological environment and adverse geological condition. There is still a lack of knowledge of the seismic behavior and performance of the precast pile foundation. In this study, a 1/8 scaled model of precast pile foundation with elevated cap is fabricated for quasi-static test. The failure mechanism and responses of the precast pile-soil interaction system are analyzed. It is shown that damage occurs primarily in precast pile-soil interaction system and the bridge pier keeps elastic state because of its relatively large cross-section designed for railways. The vulnerable part of the precast pile with elevated cap is located at the embedded section, but no plastic hinge forms along the pile depth under cyclic loading. Hysteretic curves show no significant strength degradation but obvious stiffness degradation throughout the loading process. The energy dissipation capacity of the precast pile-soil interaction system is discussed by using index of the equivalent viscous damping ratio. It can be found that the energy dissipation capacity decreases with the increase of loading displacement due to the unyielding pile reinforcements and potential pile uplift. It is expected to promote the use of precast pile foundation in accelerated bridge construction (ABC) of railways designed in seismic regions.

• Journal of Astronomy and Space Sciences
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• v.27 no.3
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• pp.205-212
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• 2010

To better understand the physical processes that maintain the high-latitude lower thermospheric dynamics, we have identified relative contributions of the momentum forcing and the heating to the high-latitude lower thermospheric winds depending on the interplanetary magnetic field (IMF) and altitude. For this study, we performed a term analysis of the potential vorticity equation for the high-latitude neutral wind field in the lower thermosphere during the southern summertime for different IMF conditions, with the aid of the National Center for Atmospheric Research Thermosphere-Ionosphere Electrodynamics General Circulation Model (NCAR-TIEGCM). Difference potential vorticity forcing and heating terms, obtained by subtracting values with zero IMF from those with non-zero IMF, are influenced by the IMF conditions. The difference forcing is more significant for strong IMF $B_y$ condition than for strong IMF $B_z$ condition. For negative or positive $B_y$ conditions, the difference forcings in the polar cap are larger by a factor of about 2 than those in the auroral region. The difference heating is the most significant for negative IMF $B_z$ condition, and the difference heatings in the auroral region are larger by a factor of about 1.5 than those in the polar cap region. The magnitudes of the difference forcing and heating decrease rapidly with descending altitudes. It is confirmed that the contribution of the forcing to the high-latitude lower thermospheric dynamics is stronger than the contribution of the heating to it. Especially, it is obvious that the contribution of the forcing to the dynamics is much larger in the polar cap region than in the auroral region and at higher altitude than at lower altitude. It is evident that when $B_z$ is negative condition the contribution of the forcing is the lowest and the contribution of the heating is the highest among the different IMF conditions.

• Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.250-265
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• 2016

Owing to our rapidly aging society, accessibility evaluation to enhance the ease and safety of access to indoor and outdoor environments for the elderly and disabled is increasing in importance. Accessibility must be assessed not only from the general standard aspect but also in terms of physical and cognitive friendliness for users of different ages, genders, and abilities. Meanwhile, human behavior simulation has been progressing in the areas of crowd behavior analysis and emergency evacuation planning. However, in human behavior simulation, environment models represent only "as-planned" situations. In addition, a pedestrian model cannot generate the detailed articulated movements of various people of different ages and genders in the simulation. Therefore, the final goal of this research was to develop a virtual accessibility evaluation by combining realistic human behavior simulation using a digital human model (DHM) with "as-is" environment models. To achieve this goal, we developed an algorithm for generating human-like DHM walking motions, adapting its strides, turning angles, and footprints to laser-scanned 3D as-is environments including slopes and stairs. The DHM motion was generated based only on a motion-capture (MoCap) data for flat walking. Our implementation constructed as-is 3D environment models from laser-scanned point clouds of real environments and enabled a DHM to walk autonomously in various environment models. The difference in joint angles between the DHM and MoCap data was evaluated. Demonstrations of our environment modeling and walking simulation in indoor and outdoor environments including corridors, slopes, and stairs are illustrated in this study.

• Journal of radiological science and technology
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• v.43 no.2
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• pp.105-114
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• 2020

This study aimed to assess of beam-matching accuracy for an 8 MV beam between the same model linear accelerators(Linac) commissioned over two years. Two models were got the customer acceptance procedure(CAP) criteria. For commissioning data for beam-matched linacs, the percentage depth doses(PDDs), beam profiles, output factors, multi-leaf collimator(MLC) leaf transmission factors, and the dosimetric leaf gap(DLG) were compared. In addition, the accuracy of beam matching was verified at phantom and patient levels. At phantom level, the point doses specified in TG-53 and TG-119 were compared to evaluate the accuracy of beam modelling. At patient level, the dose volume histogram(DVH) parameters and the delivery accuracy are evaluated on volumetric modulated arc therapy(VMAT) plan for 40 patients that included 20 lung and 20 brain cases. Ionization depth curve and dose profiles obtained in CAP showed a good level for beam matching between both Linacs. The variations in commissioning beam data, such as PDDs, beam profiles, output factors, TF, and DLG were all less than 1%. For the treatment plans of brain tumor and lung cancer, the average and maximum differences in evaluated DVH parameters for the planning target volume(PTV) and the organs at risk(OARs) were within 0.30% and 1.30%. Furthermore, all gamma passing rates for both beam-matched Linacs were higher than 98% for the 2%/2 mm criteria and 99% for the 2%/3 mm criteria. The overall variations in the beam data, as well as tests at phantom and patient levels remains all within the tolerance (1% difference) of clinical acceptability between beam-matched Linacs. Thus, we found an excellent dosimetric agreement to 8 MV beam characteristics for the same model Linacs.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.5
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• pp.22-31
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• 2006

AnnAGNPS model would be applied to simulate the pollutant removal capacity with the buffer strip in the Deachung reservoir watershed. In 2002, 2,270 tons of TN and 221 tons of TP were discharged from the nonpoint source pollutants in this watershed. During the rainy season, from June to September, 66.4% of TN and 71.9% of TP resulted from nonpoint source loads. AnnAGNPS model was also used to simulate the nutrients removal capacity from the buffer strip under the condition that the present landuse would be changed to forest. As the result of simulation, the removal rates of nutrients from the buffer strip of Daecheong reservoir watershed are 406 tons of TN, 39 tons of TP, which means reduction rates are TN 17.9%, TP 17.8%, respectively.

• Environmental and Resource Economics Review
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• v.18 no.3
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• pp.393-430
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• 2009

This study uses a computable partial-equilibrium model of the U.S. energy industry to evaluate sulfur dioxide concentrations under two environmental policies. The policies, generator-level emission caps and tradable allowances, are selected to yield identical aggregate emissions. Regional concentrations are found to vary across the two policies significantly. These variations translate into different losses for individual states, and, nationwide, to differences of hundreds of millions of dollars in aggregate health damages. Emission caps outperform allowances by $452 million. Caps favor the southwestern, south-central and southeastern states, where they deliver $840 million lower damages than the other policies, while they deliver $390 million higher damages In northern and northeastern states.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.12 no.3
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• pp.427-435
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• 1999

In the field of shape optimum design, much efforts are needed in regridding method and shape design sensitivity analysis. In this paper, Bezier curve is used to make the boundary of a structure and the improved direct differentiation method is used to calculate the shape design sensitivity. To regrid the finite element model, modified displacement field is presented in this paper. The modified displacement field makes more fine grid at large curvature. The purpose of this paper is to obtain the optimum shape of a cantilever with weight and a 3-dimensional journal bearing cap.