• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.2
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• pp.89-101
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• 2017

The study used GIS methods to analyze a business district consisting of traditional markets and large-scale stores, to determine the level of support needed for small enterprises in an urban area of Changwon-si, Gyeongsangnam-do. Data gathered on the area was analyzed using GIS tools such as Kernel density, Network analysis, and Huff modeling. Traditional markets are concentrated in areas where large-scale stores are located, and data analyses show that the number of consumer'use of large-scale stores (157,071) was three times that of traditional markets (59,953). One explanation for these results is that the large-scale stores are located either in densely populated areas or are adjacent to the traditional markets. Therefore, standards and regulations are needed to support small enterprise business districts. In the future, the results of this study can be used as a reference for planning and supporting traditional market business districts.

• International Journal of Naval Architecture and Ocean Engineering
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• v.6 no.2
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• pp.380-391
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• 2014

In this study, the scale effect on the performance of the podded propeller of tractor type is investigated. Turbulent flow computations are carried out for Reynolds numbers increasing progressively from model scale to full scale using the CFD analysis. The result of the flow calculation for model scale Reynolds numbers agrees well with that of the experiment of a large cavitation tunnel. The existing numerical analysis indicates that the performance of the podded propeller blades is mainly influenced by the advance coefficient and relatively little by the Reynolds number. However, the drag of pod housing with propeller in operation is different from that of pod housing without propeller due to the acceleration and swirl of propeller slipstream which is altered by propeller loading as well as the pressure recovery and friction according to Reynolds number, which suggests that the pod housing drag under the condition of propeller in operation is the key factor of the scale effect on the performance between model and full scale podded propellers. The so called 'drag ratio', which is the ratio of pod housing drag to total thrust of podded propeller, increases as the advance coefficient increases due to accelerated flow in the slipstream of the podded propeller. However, the increasing rate of the drag ratio reduces continuously as the Reynolds number increases from model to full scale progressively. The contribution of hydrodynamic forces, which acts on the parts composed of the pod housing with propeller operating in various loading conditions, to the thrust and the torque of the total propeller unit are presented for a range of Reynolds numbers from model to full scales.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.477-482
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• 2004

Shock waves form in the intergalactic space as an ubiquitous consequence of cosmic structure formation. Using N-body/hydrodynamic simulation data of a ACDM universe, we examined the properties of cosmological shock waves including their morphological distribution. Adopting a diffusive shock acceleration model, we then calculated the amount of cosmic ray energy as well as that of gas thermal energy dissipated at the shocks. Finally, the dynamical consequence of those cosmic rays on cluster properties is discussed.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.856-861
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• 1989

The control of a class of large scale systems formed by an arbitrary linear interconnections of linear time-invariant subsystems with unknown parameters is investigated. An approach is developed for improving the robustness of such a large scale system. In doing so, the new parameter adaptation algorithm(PAA) is used and a sufficient condition of stability is discussed by using the sector theory.

• 한국전산유체공학회:학술대회논문집
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• 2006.05a
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• pp.21-26
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• 2006

A large-scale finite element simulation and modeling method is presented for environmental flows in urban area. Parallel stabilized finite element method based on domain decomposition method is employed for the numerical simulation. Several GIS and CAD data are used for the preparation of the shape model for landform and urban structures. The present method Is applied to the simulation of flood flow and wind flow In urban area. The present method is shown to be a useful planning and design tool for the natural disasters and the change of environments in urban area.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.211-211
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• 2015

Mekong River is the world's $10^{th}$ longest river and runs through China's Yunnan province, Burma, Thailand, Laos, Cambodia and Vietnam. And Tonle Sap Lake, the largest fresh water body in Southeast Asia and the heart of Mekong River system, covers an area $2,500-3,000Km^2$ in dry season and $10,000-16,000Km^2$ in wet season. As previously noted, the water within Sap river flows from the Mekong River to Tonle Sap Lake in flood season (between June and October) and backward to Mekong River in dry season. Recently the flow regime of Sap River might be significantly affected by the development of large dams in upstream region of Mekong River. This paper aims at basic study about the large scale flood inundation of Cambodia using by CAESAR-Lisflood. CAESAR-Lisflood is a geomorphologic / Landscape evolution model that combines the Lisflood-FP 2d hydrodynamic flow model (Bates et al, 2010) with the CAESAR geomorphic model to simulate flow hydrograph and erosion/deposition in river catchments and reaches over time scales from hours to 1000's of years. This model is based on the simplified full Saint-Venant Equation so that it can simulate the interacted flow of between Mekong River and Tonle Sap Lake especially focusing on the flow direction change of Sap River by season.

• Journal of Ocean Engineering and Technology
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• v.32 no.5
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• pp.351-360
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• 2018

The construction of large scale harbor structures at Maengbang beach, which is located on the eastern coast of Korea, is of great concern because it may cause disastrous beach erosion in the vicinity. Therefore, a hydraulic model experiment was conducted to examine the morphological changes after such construction. The water depth was scaled using the method of Van Rijn (2010), which is a well-known scale law, but the results appeared to be overestimated. The present study developed a new scale law that applies an equilibrium beach profile formula to scale the model evolution to the prototype scale. When compared with survey data observed at Maengbang beach, the proposed method showed better agreement than the method of Van Rijn (2010).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.2
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• pp.132-138
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• 2011

In the present article, we investigate numerically turbulent flow of air through compound rectangular channels. Large eddy simulation(LES) is employed for unsteady turbulence modeling. LES gives better predictions for the axial mean velocity distribution than those of other turbulent models. Strong large-scale quasi-periodic flow oscillations are observed in most of the geometries investigated. Such large-scale flow oscillations in compound rectangular channels are similar to the quasi-periodic flow pulsation through the gaps between fuel rod bundle in nuclear reactor. It exists in any longitudinal connecting gap between two flow channels. The frequency of this flow oscillation is determined by the geometry of the gap. The large scale cross motions through the rectangular compound channels induce significant heat transfer enhancement of the compound channel flow.

• Wind and Structures
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• v.10 no.4
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• pp.315-346
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• 2007

A preceding companion article introduced the slot jet approach for large-scale quasi-steady modelling of a downburst outflow. This article extends the approach to model the time-dependent features of the outflow. A two-dimensional slot jet with an actuated gate produces a gust with a dominant roll vortex. Two designs for the gate mechanism are investigated. Hot-wire anemometry velocity histories and profiles are presented. As well, a three-dimensional, subcloud numerical model is used to approximate the downdraft microphysics, and to compute stationary and translating outflows at high resolution. The evolution of the horizontal and vertical velocity components is examined. Comparison of the present experimental and numerical results with field observations is encouraging.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.2
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• pp.109-115
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• 2014

Analyzing large scale data has become an important activity for many organizations. Since MapReduce is a promising tool for processing the massive data sets, there are increasing studies to evaluate the performance of various algorithms related to MapReduce. In this paper, we first develop a simulation framework that includes MapReduce workload model, data center model, and the model of data access pattern. Then we propose two algorithms that can reduce the energy consumption of MapReduce systems. Using the simulation framework, we evaluate the performance of the proposed algorithms under different application characteristics and configurations of data centers.