• Journal of the Korean Institute of Landscape Architecture
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• v.36 no.5
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• pp.1-12
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• 2008

Since the late 20th century, post-modern society has needed new styles in environmental design. The land art begun during that time supplied the momentum for the birth of the hybrid environmental design. The new design approach, focusing on land form and landscaping begun with land-form architecture, raised a powerful current of hybridization in the environmental design genres. The new picturesque landscape design distinguished by manipulated land forms and sublimated aesthetics appeared under the influence of land art and land-form architecture. Similarly, landscape urbanism was formed by the fusion of landscape architecture and urbanism. Therefore, the representative hybrid styles in environmental design appear as new picturesque landscape design, land-form architecture and landscape urbanism. With the new, strong interest in land and landscape, this same new interest was given to 'time' on account of the dynamics and indeterminacy of urban society. This new interest in land and time gave rise to new hybrid methodologies for environmental design such as mapping, diagramming and folding. These three tools have been applied most comprehensively in landscape urbanism. The 'fold' is the most popular design tool for most of the hybrid genres. The 'diagram' is the second-most popular design tool mostly for landscape urbanism and land-form architecture. Mapping is being actively applied to landscape urbanism and passively applied in new picturesque landscape design. In general, landscape urbanism seems to be a timely and suitable alternative for contemporary urban society. It displays very high potentials in the regeneration of the locality through the comprehensive hybrid methodology. It is necessary to actively engage in and develop landscape urbanism fit the local needs.

• Journal of Energy Engineering
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• v.24 no.1
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• pp.114-122
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• 2015

In the high convective gas flow condition, irregular shaped water waves from which droplet entrainment occurs are generated under horizontally stratified two-phase flow condition. KAERI proposed a new mechanistic droplet entrainment model based on the momentum balance equation consisting of the shear stress, surface tension, and gravity forces. However, this model requires correlation or experimental data of several physical parameters related to the wave characteristics. In the present study, we tried to measure the physical parameters such as wave slope, wave hypotenuse length, wave velocity, wave frequency, and wavelength experimentally. For this, an experiment was conducted in the horizontal rectangular channel of which width, height, and length are, respectively, 40 mm, 50 mm, and 4.2 m. In the present test, the working fluids are chosen as air and water. The PIV technique was applied not only to obtain images for phase interface waves but also to measure the velocity field of the water flow. Additionally, we developed the parallel wire conductance probe for the confirmation of wave height from PIV image. Finally, we measured the physical parameters to be used in the validation of new droplet entrainment model.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.2
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• pp.123-136
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• 1996

A three-dimensional Galerkin-FEM model which can handle the temporal and spatial variation of density is presented. The hydrostatic approximation is used and density effects are included by means of conservation equation of heat and the equation of state. The finite difference grids are used in the horizontal plane and a set of linear-shape functions is used for the vertical expansion. The similarity transform is introduced to solve resultant matrix equations. The proposed model was first applied to the density-driven circulation in an idealized basin in the presence of the heat exchange between the air and the sea. The advection terms in the momentum equation were ignored, while the convection terms were retained in the heat equation. Coefficients of the vertical eddy viscosity and diffusivity were fixed to be constant. Calculation in a non-rotating idealized basin shows that the difference in heat capacity with depth gives rise to the horizontal gradient of temperature. Consequently, there is a steady new in the upper layer in the direction of increasing depth with compensatory counter flow .in the lower layer. With Coriolis force, geostrophic flow was predominant due to the balance between the pressure gradient and the Coriolis force. As a test in region of irregular topography, the model is applied to the Yellow Sea. Although the resultant flow was very complex, the character of the flow Showed to be geostrophic on the whole.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.2
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• pp.70-80
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• 2000

Princeton Ocean Model (POM) is modified to construct a three-dimensional, semi-implicit hydro¬dynamic model with a wetting-and-drying scheme. The model employs semi-implicit treatment of the barotropic pressure gradient terms and the vertical mixing terms in the momentum equations, and the velocity divergence term in the vertically-integrated continuity equation. Such treatment removes the external mode and thus the mode splitting scheme in POM, allowing the semi-implicit model to use a larger time step. Applied to hypothetical systems, both the semi-implicit model and POM give nearly the same results. The semi-implicit model, however, runs approximately 4.4 times faster than POM showing its improved computational efficiency. Applied to a hypothetical system with intertidal flats, POM employing the mode splitting scheme produces noises at the intertidal flats, that propagate into the main channel resulting in unstable current velocities. Despite its larger time step, the semi-implicit model gives stable current velocities both at the intertidal flats and main channel. The semi-implicit model when applied to Kyeonggi Bay gives a good reproduction of the observed tides and tidal currents throughout the modeling domain, demonstrating its prototype applicability.

• Journal of Korea Technology Innovation Society
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• v.14 no.2
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• pp.320-342
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• 2011

This paper tries to analyze the evolution of technological innovative pattern in system semiconductor industry from the perspective of the evolution of way by which knowledge is generated and its related evolution of inter-firm relationships. In particular, this paper focuses on the evolution of knowledge after the emergence of EDA as a design tool, as a main momentum. As a result of analysis, we can find out following things. First, the innovative activities have evolved from design activity-centered technology development to innovative activities focusing on searching activities for utilizing knowledge and technology. Second, with rising value of knowledge, creation of new market utilizing knowledge, and development of new industry and new technology through inter-firm relationship had been made, in addition to strengthened specialized technological division of labor. Third, with focusing on utilization of knowledge, inter-firm network has taken diverse forms for building complementary platform for co-development. This discussion can give an insight on the necessity of utilizing inter-firm network strategically and setting strategies for enhanced searching activities such as market creation and knowledge utilization.

• Resources Recycling
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• v.18 no.2
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• pp.39-50
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• 2009

Portland cement production is under critical review due to high amount of $CO_2$ gas released to the atmosphere. Attempts to increase the utilization of fly ash, a by-products from thermal power plant to partially replace the cement in concrete are gathering momentum. But most of fly ash is currently dumped in landfills, thus creating a threat to the environment. Many researches on alkali-activated concrete that does not need the presence of cement as a binder have been carried out recently. Instead, the source of material such as fly ash, that are rich in Silicon(Si) and Aluminium(Al), are activated by alkaline liquids to produce the binder. Hence concrete with no cement is effective in the reduction of $CO_2$ gas. In this study, we investigated the influence of the compressive strength of mortar on alkaline activator and curing condition in order to develop cementless fly ash based alkali-activated concrete. In view of the results, we found out that it was possible for us to make alkali-activated mortar with 70MPa at the age of 28days by using alkaline activator manufactured as 1:1 the mass ratio of 9M NaOH and sodium silicate and applying the atmospheric curing after high temperature at $60^{\circ}C$ for 48hours.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.8
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• pp.711-719
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• 2017

Bladeless fan is becoming increasingly popular owing to its advantages, such as improved safety, easy to clean, and attractive shape. However, many people are reluctant to purchase it because of several disadvantages, such as noise and moderate wind; therefore, research on how improve wind generation without increasing the motor speed is required. This study investigates the optimization of the shape of the nozzle and nearby surface using CFD (Computational Fluid Dynamics) simulation, ANSYS fluent. The results are analyzed by ANOM (analysis of mean) and interaction analysis; therefore this study suggests the variables of affecting Coanda effect and satisfy the govern equation, the conservation of momentum. The optimal combination was found through a predictive equation. In this study, factors and levels that affect the mass flow rate were selected and experimental points were arranged using the orthogonal array table. The value of the mass flow rate was confirmed by ANSYS fluent, which is a CFD program. Through the ANOM, it was confirmed that the nozzle distance is the most influential parameter affecting the mass flow rate. Furthermore, the mass flow rate obtained from the predictive equation and the mass flow rate from the CFD correspond to the largest values. Results from this study confirmed that the mass flow rate is increased by a change in the shape, even if the motor speed did not increase.

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.1
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• pp.90-104
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• 2015

The purpose of this paper is to build a spatio-temporal evapotranspiration(ET) estimation model using Terra MODIS satellite image and by calibrating with the flux tower ET data from watershed. The fundamentals of spatial ET model, Surface Energy Balance Algorithm for Land(SEBAL) was adopted and modified to estimate the daily ET of Yongdam Dam watershed in South Korea. The daily Normalized Distribution Vegetation Index(NDVI), Albedo, and Land Surface Temperature(LST) from MODIS and the ground measured wind speed and solar radiation data were prepared for 2 years(2012-2013). The SEBAL was calibrated with the forest ET measured by Deokyusan flux tower in the study watershed. Among the model parameters, the important parameters were surface albedo, NDVI and surface roughness in order for momentum transport during calculation of sensible heat flux. As a result of the final calibration, the monthly averaged albedo and NDVI were used because the daily values showed big deviation with unrealistic change. The determination coefficient($R^2$) between SEBAL and flux data was 0.45. The spatial ET reflected the geographical characteristics showing the ET of lowland areas was higher than the highland ET.

• Korean Journal of Social Welfare Studies
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• v.48 no.1
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• pp.91-111
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• 2017

Purposes of this study, summoning thoughts and activities of Toynbee Hall of the UK and Hull House of the US held in between the end of 19C and the early 20C, are two folded: first, it is to examine the momentum and aims for which 'social' work was progressively established at that time; second, it is to look for implications for today's social work practice through understanding their characteristic activities and the context in which 'social' work was devised as an alternative in the two nations. The study method mainly relies on literature review, but further goes on to analyze the spirit of the age when settlement house was constructed as a welfare space and activities, leadership demonstrated in there, and to draw meanings for today, in terms of three dimensions: aim and location, professionality and education, and social action. Some of useful findings are: first, the COS and settlement house need to be considered in a continuum of socially responsive remedies against poverty and social work practice was developed in the process of 'suggestion-performance-critique-alternative suggestion-emergence of social work', rather than contrasting the two as opposite roots of social work practice. Second, settlement house was a socially constructed welfare space that contained intersectional dynamics of class, gender, personal vs. social, private vs. public, surrounding poverty issue. Third, besides differences between the two settlements, both purported for public goods and well-being and tried to realize the 'social' in that society. Lastly, this study explored historical meanings of settlement house as the welfare space with critical questions and discussed implications for social work practice today.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.1
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• pp.52-57
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• 2018

This paper presents the design and cold flow test results of oxidizer-rich preburner injectors for a 9 tonf-class staged combustion engine cycle. Three types of coaxial swirl injectors were designed, and 12 injectors were designed for each type. The diameters of the fuel tangential holes are identical. The diameters of the oxidizer tangential holes were varied to investigate the influence of combustion in the oxidizer-rich preburner according to the momentum ratio of the gas oxidizer generated from combustion in the injector chamber and liquid oxidizer through the cooling channel. It will be verified through a powerpack and combustion test using an oxidizer-rich preburner. In the cold flow test, the fuel flow rate and oxidizer tangential hole flow rate reached the target value based on the designed differential pressure.