• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.5
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• pp.133-140
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• 2019

Building Information Modeling (BIM) and modular construction are regarded as important technologies that could contribute to overcoming the crisis faced by the construction industry. However, BIM uptake in current modular construction projects is limited. Moreover, there are no specific guidelines to support decision-making regarding the application of BIM in modular construction projects. Therefore, this study aims to analyze the possibility for BIM uptake in each phase of modular construction projects in Korea. Initially, the literature detailing on BIM uptake cases in modular construction projects was reviewed. The detailed work and activities for each phase of a modular project were analyzed via a questionnaire targeting domestic modular experts, to derive items requiring improvement due to errors or changes occurring in the actual project. Ten realistic BIM uptake items were derived, reflecting the results of literature review and expert interviews. Then, the BIM uptake items in each phase were analyzed in terms of necessity and efficiency via a second questionnaire using five-point Likert scales. Finally, the BIM utilization index (BIM UI) of the BIM uptake items was suggested as a priority measure. As a result, the BIM UI of "3D coordination" (U2), "design authoring and reviews for off-site fabrication" (U3), and "detailed 3D modeling for off-site fabrication" (U4), were assigned the highest priority. The results of this study can be used as guidelines to support decision-making regarding the application of BIM in modular construction projects.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1559-1569
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• 2002

In order to investigate the characteristics of electromagnetic flowmeter in two -phase flow, an AC electromagnetic flowmeter was designed and manufactured. In various flow conditions, the signals and noises from the flowmeter were obtained and analyzed by comparison with the observed flow patterns with a high speed CCD camera. The experiment with the void simulators in which rod shaped non-conducting material was used was carried out to investigate the effect of the bubble position and the void fraction on the flowmeter. Based on the results from the void simulator, two -phase flow experiments encompassed from bubbly to slug flow regime were conducted. The simple relation $\Delta$ $U_{TP}$ = $\Delta$ $U_{SP}$ (l-$\alpha$) was verified with measurements of the potential difference and the void fraction. Due to the lack of homogeneity in a rent two -phase flow, the discrepancy between the relation and the present measurement was slightly increased with void fraction and also liquid volumetric flux jf. Whereas there is no difference in the shape of the raw signal between single-phase flow and bubbly flow, the signal amplitude for bubbly flow is higher than that for single -phase flow at the same water flow rate, since the passage area of the water flow is reduced. In the case of slug flow, the phase and the amplitude of the flowmeter output show dramatically the flow characteristics around each slug bubble and the position of a slug bubble itself. Therefore, the electromagnetic flowmeter shows a good possibility of being useful for identifying the flow regimes.ul for identifying the flow regimes.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.365-368
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• 2000

This paper describes image-rejection down conversion mixer for bluetooth application using 0.35u CMOS process. the proposed architecture is composed of LO phase shifter, mixer core, IF buffer, and IF phase shifter. IF phase shifter is designed using polyphase fillet. Simulation results show conversion gain = l0㏈, input 1㏈ compression point = -15.7㏈m. input third-order intercept point(IIP3) = -4.4㏈m, and image-rejection ratio = 37.8㏈, respectively, at 3V supply voltage, and 15.7㎃ current.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.633-634
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• 2001

The in situ immobilization of lipase in an LC column with aldehyde-silica stationary phase was optimized. The effects of feed composition, temperature, mobile phase pH and now rate on immobilization efficiency were investigated. Lipase activity after in situ immobilization was compared with free enzyme and batch immobilized enzyme.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.506-509
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• 2001

A high power U.P.S system utilizing the parallel connection of low power U.P.S is developed. For the purpose of elimination the circular current between U.P.S.s, a digital circuit is employed. Furthermore a double phase synchronization and an interphase reactor are used to eliminate the circular current and the voltage ripples caused by the system parameter unbalances of parall connected U.P.S.s. The digital controller is implemented with ADSP21061 as aspect of a functional convenience.

• Journal of Life Science
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• v.18 no.1
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• pp.96-102
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• 2008

Piceatannol is a polyphenol that is found in abundant quantities in grapes and wine. Although recent experimental data revealed the anti-cancer potency of piceatannol, the molecular mechanisms underlying the antileukemic activity have not yet been studied in detail. In the present study, we investigated further possible mechanisms by which piceatannol exerts its anti-proliferative action in cultured human leukemia U937 cells. Exposure of U937 cells to piceatannol resulted in growth inhibition and induction of apoptosis as measured by MTT assay and flow cytometry analysis, which was associated with S phase arrest of the cell cycle. Piceatannol treatment markedly inhibited the activity of telomerase, and the levels of human telomerase reverse transcriptase (hTERT) and telomerase-associated protein-1 (TEP-1), main determinants of the telomerase enzymatic activity, were progressively down-regulated by piceatannol treatment in a dose-dependent fashion. However, the levels of cyclooxygenases (COXs) expression and prostaglandin E2 (PGE2) release were not changed in piceatannol-treated U937 cells. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of piceatannol.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.295-298
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• 2005

High temperature deformation behavior of $\alpha\;and\;\beta$ phase of Ti-6Al-4V was investigated within the framework of a self-consistent approach at various temperature ranges. To examine the flow behavior of u-phase, Ti-7.0Al-1.5V alloy was used, whose chemical composition is close to that of the $\alpha$ phase in Ti-6Al-4V at hot working temperatures. The flow stress of $\beta$ phase was predicted by using self-consistent approach. The flow stress of $\alpha$ phase was higher than that of $\beta$ phase above $750^{\circ}C$, while the $\beta$ phase revealed higher flow stress than a phase at $650^{\circ}C$. It was found that the relative strength and strain rate ratio between $\alpha\;and\;\beta$ phase significantly varied with temperature. From this approach, the mode for grain matrix deformation was proposed as a mixed type of both iso-stress and iso-strain rate modes.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.3
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• pp.145-152
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• 2001

Low Rayleigh number thermal convection in a fluid layer confined between two-infinite horizontal walls kept at spatially sinusoidal temperature distributions, T_L=T_m+\Delta T\sin \kappax,\;T_U=T_m+\Delta T\sin(\kappax-\beta)$, is theoretically investigated by a regular perturbation expansion method. For small wave numbers, an upright cell is formed between the two walls at $\beta$=0. The cell is tilted, as the phase difference increases, and a flow with tow counter-rotating eddies occurs at $\beta=\pi$. when the wave number is large, isolated eddies are formed near the lower and upper walls, for all the phase differences. There exists a wave number at which maximum heat transfer rate at the walls occurs, at each of the phase differences. And the wave number increases with increase of the phase difference. for a fixed wave number, the heat transfer rate decrease with increase of the phase difference.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2070-2072
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• 2002

In this paper, advance angle control is described to drive an industrial low voltage SRM(Switched reluctance motor) for a forklift truck by changing velocity and torque. The high current SRM is designed and its phase resistance and phase inductance are very low to inject high current into the phase windings. In this reason, the current has to be built up in the increasing phase inductance part as soon as possible. Therefore, the phase switch must be turned on before the phase inductance increases, and this angle is called as the advance angle. We analyze the changes of the advance angle as its torque and velocity are changed in the real SRM driving experiment. And we propose the way to improve the SRM performance by using the advance angle control.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.9
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• pp.461-466
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• 1999

The switched reluctance motor (SRM) would have torque ripple if not operated with an MMF waveform specified for switching angle and phase voltage. This paper describes the robustic control scheme that permits the phase torque to be flat by PLL(Phase Locked Loop) controller. In this control scheme, the locked phase signal of PLL controls the switching dwell angle and it's loop filter signal controls the switching voltage adaptively. Experimental results show that stable dynamic performance is obtained for torque and speed together with low torque ripple on the operation of variable loads.