• Structural Engineering and Mechanics
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• v.66 no.3
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• pp.411-421
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• 2018

Although a rubber isolation cushion can reduce the dynamic response of a structure itself, it has little influence on the height of a sloshing wave and even may induce magnification action. Vertical baffles are set into a base-isolated Concrete Rectangular Liquid Storage Structure (CRLSS), and baffles are opened as holes to increase the energy dissipation of the damping. Problems of liquid nonlinear motion caused by baffles are described using the Navier-Stokes equation, and the space model of CRLSS is established considering the Fluid-Solid Interaction (FSI) based on the Finite Element Method (FEM). The dynamic response of an isolated CRLSS with various baffles under an earthquake is analyzed, and the results are compared. The results show that when the baffle number is certain, the greater the number of holes in baffles, the worse the damping effects; when a single baffle with holes is set in juxtaposition and double baffles with holes are formed, although some of the dynamic response will slightly increase, the wallboard strain and the height of the sloshing wave evidently decrease. A configuration with fewer holes in the baffles and a greater number of baffles is more helpful to prevent the occurrence of two failure modes: wallboard leakage and excessive sloshing height.

• Progress in Medical Physics
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• v.15 no.4
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• pp.247-254
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• 2004

According to developing high energy linear accelerators and treatment methods, like (3 dimensional conformal radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT), many radiotherapy centers are replacing older linear accelerators with new higher technical machines. This often presents a shielding problem as the designed shield for the existing rooms is not adequate for the higher technical machines. Additional shielding in limited existing space becomes necessary. We are replacing older brachytherapy room with new higher technical linear accelerator for IMRT. This room is not adequate for the IMRT machine without additional shielding design. The logical development of optimum structural shielding designs with concrete and high density shielding blocks are presented. We obtained following results by comparison between the pre-calculating values and actual survey of completed LINAC installation. High density shielding blocks have more powerful radiation protection about 2 times.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.12
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• pp.579-587
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• 2014

This paper deals with precise analytical state equation modeling of a variable speed refrigeration system (VSRS) for optimum control in state space. The VSRS is described as multi-input and multi-output (MIMO) system, which has two controlled variables and two control inputs. First, the Navier-Stokes equation and mass flow rate were applied to each component of the basic refrigeration cycle to build a dynamic model. The dynamic model, represented by a differential equation, was transformed into the state equation formula. Next, a full-order state observer was built to estimate all of the state variables to compose an optimum control system. Then, an optimum controller was designed to minimize an evaluation function that has input energy and control error. Finally, simulations and experiments were conducted to verify the validity of the proposed modeling and designed optimum controller to regulate target temperature and superheat in a 1RT oil cooler system. The results show that the proposed method, state equation modeling and optimum control, is efficient to ensure optimal control performance of the VSRS.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.12
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• pp.802-807
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• 2008

A Study on Typical Rates of Water-use for School Facilities has been carried out in this work. Water supply system is given much weight in school facilities. Therefore, it set up a basis efficiency using of water sources to calculate typical rates of water use. The results are summarized as follows; 1) On the whole, typical rates of water-use was founded out 15 L/stu. d in pirmary school, 10 L/stu. d in middle school and 30 L/stu. d in high school smaller than the existing it. It was rate of water-use change as season and Max. Rates of water-use was July. 2) I deem that school hours are 5 hour's in primary school, 7 hour's in middle school and 8 hour's in high school. It the concept of 1 hour that is lesson time 40 minutes and resting time 10 minutes in primary school, lesson time 45 minutes and resting time 10 minutes in middle school and lesson time 50 minutes and resting time 10 minutes in high school. 3) It is desired that we calculate the volume of pump and water tank throughout this concept and the size of water tank should be 1.5 times with taking peak load into consideration by this study on typical rate of water-use. 4) The amount of using water increases in gradually and I consider the life cycle of facilities is more than 10 years. As a result, I can forecast that the size will be insufficiency but I deem that if we devise a plan about parallel pumping on water tank space, we can cope with it. Also, it is expected that we can cut back the transport energy by controlling pump volume.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.510-515
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• 2007

A Study on Typical Rates of Water-use for School Facilities has been carried out in this work. Water supply system is given much weight in school facilities. Therefore, it set up a basis efficiency using of water sources to calculate typical rates of water use. The results are summarized as follows ; 1) On the whole, typical rates of water-use was founded out 15 L / stu. d in pirmary school, 10 L / stu. d in middle school and 30L / stu. d in high school smaller than the existing it. It was rate of water-use change as season and Max. Rates of water-use was July. 2) I deem that school hours are 5 hour's in primary school, 7 hour's in middle school and 8 hour's in high school. It the concept of 1 hour that is lesson time 40 minutes and resting time 10 minutes in primary school, lesson time 45 minutes and resting time 10 minutes in middle school and lesson time 50 minutes and resting time 10 minutes in high school. 3) It is desired that we calculate the volume of pump and water tank throughout this concept and the size of water tank should be 1.5 times with taking pick load into consideration by this study on typical rate of water-use. 4) The amount of using water increases in gradually and I consider the life cycle of facilities is more than 10 years. As a result, I can forecast that the size will be insufficiency but I deem that if we devise a plan about parallel pumping on water tank space, we can cope with it. Also, it is expected that we can cut back the transport energy by controlling pump volume.

• Journal of the Korea Society of Computer and Information
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• v.18 no.2
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• pp.1-8
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• 2013

TIn this paper, we propose a high performance L1 cache structure on the high clock CPU of 4GHz. The proposed cache memory consists of three parts, i.e., a direct-mapped cache to support fast access time, a two-way set associative buffer to exploit temporal locality, and a buffer-select table. The most recently accessed data is stored in the direct-mapped cache. If a data has a high probability of a repeated reference, when the data is replaced from the direct-mapped cache, the data is selectively stored into the two-way set associative buffer. For the high performance and low power consumption, we propose an one way among two ways set associative buffer is selectively accessed based on the buffer-select table(BST). According to simulation results, Energy $^*$ Delay product can improve about 45%, 70% and 75% compared with a direct mapped cache, a four-way set associative cache, and a victim cache with two times more space respectively.

• Journal of Digital Contents Society
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• v.18 no.2
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• pp.249-256
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• 2017

As single-person households increase, demands for self interior design has been also increasing. The furniture arrangement takes big part of interior design. But sometimes people need professional helps for the proper and effective arrangement of furniture which makes self-interior design harder. Often, people share information and advices about interior design through Social Network Service. Experts could help directly but this approach would have several issues: First, the detailed and accurate advice would be difficult because experts have to examine the space through 2D pictures or video. Second, they have to make an appointment which would cause inconvenience to both customer and expert. In this paper, the furniture arrangement application for real-time sharing of interior design based on virtual reality is proposed to make up for the weak points. People can precisely share information and advice about self-interior design through this application in realtime, reducing waste of time and energy.

• Journal of Korean Association for Spatial Structures
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• v.13 no.2
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• pp.83-91
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• 2013

The core aim of this dissertation is to empirically scrutinize a strength characteristic of beam-column frame subjected to the cyclic lateral load, a beam-column frame of un-reinforced masonry wall, and a shear wall frame. First and foremost, I embark upon making three prototypes vis-$\grave{a}$-vis this research. By conducting this process, I touch on an analysis of cyclic behavior and a damage characteristic of the beam-column frame, the beam-column frame of un-reinforced masonry wall, and the shear wall frame. What is more, through the previous procedure, the next part delves into the exact stress transfer path and the destructive mechanism to examine how much and how strong the beam-column frame of un-reinforced Masonry Wall does have a resistance capacity against earthquake in all the architecture constructed by the above-mentioned frame, as well as school buildings. In addition to the three prototypes, two more experimental models, a beam-column frame and shear wall frame, are used to compare with the beam-column frame of un-reinforced masonry wall. Lastly, the dissertation will suggest some solutions to improve the resistance capacity against earthquake regarding all constructions built with non bearing wall following having examining precisely all the analysis with regard to not only behavior properties and the damage mechanism of the beam-column frame and the beam-column frame of un-reinforced Masonry Wall but also the resistance capacity against earthquake of non bearing wall and school buildings.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.262-270
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• 2004

Basic experiments were carried out using the THT-IV low-power Hall thruster to examine the influences of magnetic field shape and strength, and acceleration channel length on thruster performance and to establish guidelines for design of high-performance Hall thrusters. Thrusts were measured with varying magnetic field and channel structure. Exhaust plasma diagnostic measurement was also made to evaluate plume divergent angles and voltage utilization efficiencies. Ion current spatial profiles were measured with a Faraday cup, and ion energy distribution functions were estimated from data with a retarding potential analyzer. The thruster was stably operated with a highest performance under an optimum acceleration channel length of 20 mm and an optimum magnetic field with a maximum strength of about 150 Gauss near the channel exit and with some shape considering ion acceleration directions. Accordingly, an optimum magnetic field and channel structure is considered to exist under an operational condition, related to inner physical phenomena of plasma production, ion acceleration and exhaust plasma feature. A new Hall thruster was designed with basic research data of the THT-IV thruster. With the thruster with many considerations, long stable operations were achieved. In all experiments at 200-400 V with 1.5-3 mg/s, the thrust and the specific impulse ranged from 15 to 70 mN and from 1100 to 2300 see, respectively, in a low electric power range of 300~1300 W. The thrust efficiency reached 55 %. Hence, a large map of the thruster performance was successfully made. The thermal characteristics were also examined with data of both measured and calculated temperatures in the thruster body. Thermally safe conditions were achieved with all input powers.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.691-698
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• 2017

In this study, the injector transfer function (ITF) of a gas-gas coaxial jet-swirl injector is measured by applying excitation to jet or swirl flow using a loudspeaker. As a result of measuring the ITF according to the variation of feed system length, the ITF peak occurs at the resonance frequency of the space where the perturbed flow passes. When applying the excitation to the jet flow, as the jet flow increases up to 56 slpm, the magnitude of ITF decreases, and ITF increases thereafter. Therefore the larger the velocity difference between the jet and the swirl flow, the larger the ITF. In the case of the swirl excitation, the ITF decreases as the jet flow increases because of the decrease of the energy with respect to the constant flow at the downstream. This difference is caused by the location of the hot wire anemometer on the downstream of the injector center axis.