• Korean Journal of Human Ecology
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• v.12 no.5
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• pp.579-593
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• 2003

The purpose of this study was to investigate the social support, understanding of the children's problem in the female-headed single parents, and their child rearing methods. To obtain this purpose, in-depth interview was conducted to 8 female-headed single parents from March 3 to April 5, 2003. The contents of interviews were recorded and analyzed by qualitative method. The results were as follows: First, female-headed single parents were stuck for the social support and the relationships with parents-in-law were ruptured, especially. Secondly, female-headed single parents had well known about their children's daily life. Third, in the early stage of female-headed single parents, they had expressed the stresses in their hardship of life to their children, but it decreased whenever they were accustomed to their life.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.271-278
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• 2016

Recently, reverse osmosis (RO) is the most common process for seawater desalination. A common problem in both RO and thermal processes is the high energy requirements for seawater desalination. The one energy saving method when utilizing the osmotic power is utilizing pressure retarded osmosis (PRO) process. The PRO process can be used to operate hydro turbines for electrical power production or can be used directly to supplement the energy required for RO desalination system. This study was carried out to evaluate the performance of both single-stage PRO process and two-stage PRO process using RO concentrate for a draw solution and RO permeate for a feed solution. The major results, were found that increase of the draw and feed solution flowrate lead to increase of the production of power density and water permeate. Also, comparison between CDCF and CDDF configuration showed that the CDDF was better than CDCF for stable operation of PRO process. In addition, power density of two-stage PRO was lower than the one of single-stage. However, net power of two-stage PRO was higher than the one of single-stage PRO.

• Korean journal of food and cookery science
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• v.24 no.4
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• pp.473-479
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• 2008

The principal objective of this study was to evaluate the sensory properties and physical characteristics of muffins produced using different fats(butter, grape seed oil) and mixing methods(Creaming method, Foam method, Single-stage method). The muffins weighed between $63.25{\sim}64.50$ g and were $5.77{\sim}6.42$ cm in height. In a texture analyzer test, muffins prepared via the single-stage method with butter evidenced the highest hardness, gumminess, and chewiness values among the five kinds of muffin prepared in these experiments. The springiness value was highest in the muffin prepared via the foam method with grape seed oil. In the sensory evaluation, we detected no significant differences among the muffins in terms of flavor($4.76{\sim}5.24$), taste($4.65{\sim}5.29$), softness ($4.65{\sim}5.41$), and overall acceptability ($4.47{\sim}5.29$). In the chemical composition analysis, moisture and crude protein contents were found to be higher in the control group(p<0.05) than in the muffin prepared via the foam method with grape seed oil(p<0.01). We noted no significant differences among the muffins in terms of crude lipids or crude ash content.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.11 no.1
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• pp.65-70
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• 2011

The increased disk rotational velocity to improve the data transfer rate has raised up many serious problems in its servo control system which should control the position and velocity of a spot relative to a rotating disk. This paper proposes gain-scheduling-based track-seek control for single stage actuator of hard disk drives. Gain scheduling is a technique that can extend the validity of the linearization approach to a range of operating points and one of the most popular approaches to nonlinear control design. The proposed method schedules controller gains to improve the transient response and minimize overshoot during the functions of the read/write head positioning servomechanism for the seek control. The validity of the proposed method is demonstrated through stability analysis and simulation results.

• The KSFM Journal of Fluid Machinery
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• v.3 no.3 s.8
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• pp.7-11
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• 2000

A numerical study based on the three-dimensional thin-layer Navier-Stokes solver is carried out to analyze the flowfield through a single stage transonic compressor. Explicit fout-step Runge-Kutta scheme with spatially variable time step and implicit residual smoothing is used. The governing equations we discretized with explcit finite difference method. Mired-out average method is used at the interface between rotor and stator. And, an artificial dissipation model is used to assure the stability of solution. The results with k-w turbulence model were compared to the results with Baldwin-Lomax model, and physical phenomena of transonic compressor are presented. The two turbulence models give the results that show reasonably good agreements with experimental data.

• The KSFM Journal of Fluid Machinery
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• v.9 no.3 s.36
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• pp.7-13
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• 2006

Shape optimization of a rotor blade in a single-stage transonic axial compressor has been performed using a response surface method and three-dimensional Navier-Stokes analysis. Two shape variables of the rotor blade, which are used to define a blade skew, are introduced to increase an adiabatic efficiency. Throughout the shape optimization of a rotor blade, the adiabatic efficiency is increased to about 2.2 percent compared to that of the reference shape of the stator. The increase in efficiency for the optimal shape of the rotor is due to the pressure enhancement, which is mainly caused by moving the separation position on the suction surface of rotor blade to the downstream direction.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.34-38
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• 2006

A low cost PDP sustain power supply is proposed based on flyback topology. By using Boundary Conduction Method(BCM) to control input current regulation, DCM condition can be met under all load conditions. Another feature of the proposed method is that a excessive voltage stress due to the link voltage increase can be suppressed by removing link capacitor and suggest new 'Level-shifting switch driver'. this new gate driver is improved 66% of efficiency than switching loss of a existed push-pull amplifier. The proposed converter is tested with a 400W(200V-2A output) prototype circuit.

• 유체기계공업학회:학술대회논문집
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• 1999.12a
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• pp.27-32
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• 1999

A numerical study based on the three-dimensional thin-layer Navier-Stokes solver is carried out to analyze the flowfield through a single stage transonic compressor. Explicit four-step Runge-Kutta scheme with spatially variable time step and implicit residual smoothing is used. The governing equations are discretized with exploit finite difference method. Mixed-out average method is used at the interface between rotor and stator. And, an artificial dissipation model is used to assure the stability of solution. The results with k-$\omega$ turbulence model were compared to the results with Baldwin-Lomax model, and physical phenomena of transonic compressor are presented. The two turbulence models give the results that show reasonably good agreements with experimental data.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.9
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• pp.590-597
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• 2000

Design of single state AC-DC converter with high power factor for low level applications is proposed. The proposed converter is obtained from the integration of a buck-boost converter and the half-bridge DC-DC converter. This converter gives the good power factor correction low line current harmonic distortions and tight output voltage regulations. This converter also has a high efficiency by employing an soft switching method and synchronous rectifier. The modelling and detailed analysis for the proposed converter are performed. To verify the performance of the proposed converter a 100W converter has been designed

• Korean Institute of Interior Design Journal
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• v.26 no.3
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• pp.71-80
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• 2017

Korea is facing various social problems including single elderly household, increase in the number of disabled people and poverty rate and a difference in the proportion of males to females between urban areas and rural areas along with the advent of rapid aging society. Especially, the ratio of poor households in rural areas residing in housing which falls below the minimum housing level and most of them are in the dead zone of housing welfare. In addition, if it is impossible for them to move (relocate) to new housing, the house remodeling is the only measure for improving their housing welfare. However, we don't have enough prior relevant academic and practical experience, and house remodeling requires a series of process including prior planning construction and post-occupancy evaluation, but almost no fundamental research that provides relevant insight has been carried out. Therefore, the purpose of this study is to describe all field situations that occur in the whole customized house remodeling process for disabled female senior citizens living alone in a rural area. The remodeling process was classified into initial planning stage, field verification and adjustment stage and construction stage as the method to participate in the field directly, and any change in the remodeling plan and its causes at each stage were analyzed. As a result, some remodeling items were changed from the main viewpoint of participating parties before the beginning of construction and for reasons such as the deterioration level of housing site, limitation in building equipment and rearrangement of housing, etc., and the remodeling method and its details were developed. It was identified that constant change that occurred in the remodeling process resulted from 1) unique poor characteristics of existing housing and 2) physical condition of residents and their unique lifestyle characteristics that were two aspects required to be emphasized by customized remodeling.