• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.2
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• pp.108-122
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• 1996

This study was to introduced estimation model for optimum probabilistic rainfall intensity on hydrological area. Originally, probabilistic rainfall intensity formula have been characterized different coefficient of formula and model following watersheds. But recently in korea rainfall intensity formula does not use unionize applyment standard between administration and district. And mingle use planning formula with not assumption model. Following the number of year hydrological duration adjust areal index. But, with adjusting formula applyment was without systematic conduct. This study perceive the point as following : 1) Use method of excess probability of Iwai to calculate survey rainfall intensity value. 2) And, use method of least squares to calculate areal coefficient for a unit of 157 rain gauge station. And, use areal coefficient was introduced new probabilistic rainfall intensity formula for each rain gauge station. 3) And, use new probabilistic rainfall intensity formula to adjust a unit of fourteen duration-a unit of fifteen year probabilistic rainfall intensity. 4) The above survey value compared with adjustment value. And use three theory of error(absolute mean error, squares mean error, relative error ratio) to choice optimum probabilistic rainfall intensity formula for a unit of 157 rain gauge station.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.11
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• pp.726-732
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• 2011

The aerodynamic and aeroacoustic performance of discharge grille of outdoor unit of air-conditioner was investigated in this study. Discharge grille is one of outdoor unit's important parts to affect the flow rate and Overall Sound Pressure Level(OSPL). New type of discharge grille was suggested based on the results of numerical simulation. To simulate the flow pattern near the propeller fan, commercial flow solver FLUENT was used. Sliding mesh method was used for rotating propeller fan and initial condition for unsteady model was calculated by Multiple Reference Frame(MRF) method. To minimize the interaction noise between fan blade wake and discharge grille, new discharge grille has radial rib which is aligned with trailing edge of fan blade. And inclined radial rib was adopted for reducing flow rate drop in discharge grille. The optimization of inclined angle of radial grille was performed experimentally.

• Journal of the Korean housing association
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• v.18 no.6
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• pp.57-67
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• 2007

The purpose of this study was to grasp major elements and actual condition of apartment unit remodeling by in-depth interviews on residents and specialists. The interviews had been conducted to interior designers who have a wide experience of apartment remodeling and residents who live in recently remodeled apartment unit. In-depth interview is a kind of qualitative method in which attention to reply of responses with open-access between interviewer and respondents. According to the results, remodeling elements were generally changing of lighting fixtures and finishing materials in the all spaces, integration of balcony into children's room, installation of furniture in kitchen and entrance, changing storage furnitures and equipments in bathroom. Artificial lighting method were selected generally whole lighting. Finishing materials were used ordinary (non environmentally-friendly) wallpaper and adhesion and tempered floor. There were unsatisfied factors after remodeling, these were dissatisfaction of design, construction defects, and stink of reflecting 'sick house'. Also they responded that they should be considering to use environmentally-friendly material at next remodeling.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1891-1898
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• 2013

To efficiently execute 3D graphic APIs, such as OpenGL and Direct3D, special purpose arithmetic unit(SFU) which supports floating-point sine, cosine, reciprocal, inverse square root, base-two exponential, and logarithmic operations is designed. The SFU uses second order minimax approximation method and lookup table method to satisfy both error less than 2 ulp(unit in the last place) and high speed operation. The designed circuit has about 2.3-ns delay time under 65nm CMOS standard cell library and consists of about 23,300 gates. Due to its maximum performance of 400 MFLOPS and high accuracy, it can be efficiently applicable to mobile 3D graphics application.

• Journal of The Korea Institute of Healthcare Architecture
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• v.21 no.4
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• pp.17-25
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• 2015

Purpose: At the moment, There is a facility standard for intensive care units on the Korea medical services Act. However, the contents of regulation are so limited and difficult to apply. Therefore, it is necessary to draw up the guideline to complement the regulation for efficient operation of intensive care units. This study aims to suggest basic data for guideline of intensive care units. Methods: 2 Methods have been used in this paper. 1) Comparative analysis between the national regulation of Korea with the design standard of the United States America, the United Kingdom and Australia. 2) A literature survey about operation method for intensive care unit, focused on materials published in intensive care medicine society of each country. Results: In comparison with guideline of abroad cases, additional supplement are required, with regard to item such as operation environment, size, nursing manpower ratio, bed space area, space program of intensive care units for healing environment. Implications: This study is a basic research for guideline of intensive care unit, and need to be followed by further study using various perspectives and methods.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.5
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• pp.82-88
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• 2008

This paper proposes a novel method of 2 dimensional shape display. Shape displays allow us to feel tile actual volume of the object, unlike conventional 2D visual displays of 3D objects. The proposed method employs a wireframe structure to present 2D or 3D objects. The wireframe is composed of small units driven by shape memory alloy (SMA) actuators. The drive unit is analogous to the agonist-antagonist system of animal musculoskeletal systems, where the SMA actuators serve as agonist and antagonist muscles. The force in the SMA actuator is controlled by electrical current. The drive unit is equipped with the locking mechanism so that it can sustain the external force exerted by the user as well as the own weight of the wireframe structure. By controlling the current into the SMA actuator and locking mechanism, we can control the angle of the drive unit. A chain of drive units enables presentation of 2 dimensional objects. 3 dimensional presentations are possible by collecting the chains of drive units.

• Nuclear Engineering and Technology
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• v.53 no.10
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• pp.3247-3255
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• 2021

As Probabilistic Safety Assessments (PSAs) are thoroughly conducted for the Site Operating States (SOSs) for a single unit, multi-unit Probabilistic Safety Assessments (MUPSAs) are ongoing worldwide to address new technical challenges or issues. In South Korea, the determination of the site operating states for a single site requires a logical approach with reasonable assumptions due to the fact that there are 4-8 operating units for each site. This paper suggests a simulation model that gives a reasonable expectation of the site operation states using the Monte-Carlo method as a stochastic approach and deterministic aspects such as operational policies. Statistical hypothesis tests were conducted so that the reliance of the simulation results can be guaranteed. In this study, 7 units of the Kori site were analysed as a case study. The result shows that the fraction of full power for all 7 units is nearly 0.45. For situations when more than two units are not in operation, the highest fraction combination was obtained for Plant Operation State (POS) 8, which is the stage of inspection and repairment. By entering various site operation scenarios, the simulation model can be used for the analysis of other site operation states.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.84-88
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• 2001

This paper proposes a method of solving a unit commitment problem using parallel tabu search (PTS). The TS is efficient optimization method using meta-heuristic. In this paper, to reduce the computation time for evaluating the neighborhoods, an evaluating method only on changed part and a path relinking method as diversification strategy are proposed. To show the usefulness of the proposed method, we simulated for 10 units system and 110 units system. Numerical results show improvements in the generation costs and the computation time compared with conventional methods. Numerical results show improvements in the generation cost and the computation time compared to previously obtained results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2098-2102
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• 2007

The conventional CCPU(Cable Covering Protective Unit) modeling methods which are used by Type 99 and Type 92 in EMTP simulation are firstly discussed in this paper, and then some problems of them are also investigated. Modeling method using Type 99 causes unstable characteristic at initial transient of CCPU operation. Time delay has also effect on the output of CCPU modeling. So, in this paper, a new modeling method for CCPU is designed by DBM(Data Base Module) of EMTP. The characteristic of Type 92 is used for the new modeling method. The reliability of this one is proved by comparing simulation with measured data. Specially, at initial transient, the waveform of the new method shows more stable result than that of conventional method using Type 99. Also, the peak value is similar to measured data.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.324-329
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• 2003

An air-conditioner has various noise sources such as cooling fan noise, pumping noise, flow noise and impact noise. Among these, impact noise is the most unpleasant source. This is because the noise is produced in indoor unit of air-conditioner. To control the noise source effectively, first we must identify the noise sources. When we identify impact noise source, the measurement have to be carried out simultaneously. So we use beamforming method that requires less measurement points than intensity method and acoustic holography. The objective of this paper is to estimate the location of impact source. This objective can be achieved by using minimum variance cepstrum that is able to detect impulse embedded in noise. In this study, modified beamforming method based on cepstrum domain is proposed. Then this method applied to air-conditioner noise sources which produce impact noise.