• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2451-2456
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• 2003

In biological cell manipulation, manual thrust or penetration of an injection pipette into an egg is currently performed by a skilled operator, relying only on visual feedback information. Massive load of various micro injection of either genes, fluid or cells in the postgenomic era calls a more reliable and automatic micro injection system that can test hundreds of genes or cell types at a single experiment. We initiated to study cellular force sensing in zebrafish eggs as the first step for the development of a more controllable micro injection system by any inexperienced operator. Zebrafish eggs at different developmental stages were collected and an integrated biomanipulation system was employed to measure cellular force during penetrating the egg envelope, the chorion. First of all, the biomanipulation system integrated with cellular force sensing instrument is implemented to measure the penetration force of cell membranes and characterize mechanical properties of zebrafish embryo cells. Furthermore, implementation of cellular force sensing system and calibration are presented. Finally, the cellular force sensing of penetrating cell membranes at each developmental stages was experimentally performed. The results demonstrated that the biomanipulation system with force sensing capability can measure cellular force at real-time while the injection operation is undergoing. The magnitude of the measured force was in the range of several hundreds of uN. The precise real-time measurement should provide the first step forwards for the development of an automatic and reliable injection system of various materials into biological cells.

• Journal of Microbiology
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• v.45 no.1
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• pp.41-47
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• 2007

The Hantaan virus (HTNV) is an enveloped virus that is capable of inducing low pH-dependent cell fusion. We molecularly cloned the viral glycoprotein (GP) and nucleocapsid (NP) cDNA of HTNV and expressed them in Vero E6 cells under the control of a CMV promoter. The viral gene expression was assessed using an indirect immunofluorescence assay and immunoprecipitation. The transfected Vero E6 cells expressing GPs, but not those expressing NP, fused and formed a syncytium following exposure to a low pH. Monoclonal antibodies (MAbs) against envelope GPs inhibited cell fusion, whereas MAbs against NP did not. We also investigated the N-linked glycosylation of HTNV GPs and its role in cell fusion. The envelope GPs of HTNV are modified by N-linked glycosylation at five sites: four sites on G1 (N134, N235, N347, and N399) and one site on G2 (N928). Site-directed mutagenesis was used to construct eight GP gene mutants, including five single N-glycosylation site mutants and three double-site mutants, which were then expressed in Vero E6 cells. The oligosaccharide chain on residue N928 of G2 was found to be crucial for cell fusion after exposure to a low pH. These results suggest that G2 is likely to be the fusion protein of HTNV.

• The Journal of the Acoustical Society of Korea
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• v.28 no.1
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• pp.70-76
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• 2009

In speech communications in noisy environments, speech intelligibility is seriously degraded due to the masking effect of ambient noise. In this paper, a new method to improve speech intelligibility in noisy environments is proposed. Based on the perception theory that the temporal envelope plays a major role in determining intelligibility, the proposed method uses a novel operation that enhances the fluctuation of band-wise temporal envelope and also contains pitch enhancement for improving speech naturalness. In addition, a new subjective evaluation scheme employing binaural listening is proposed in order to measure more reliable performance. The subjective performance measured with the proposed scheme shows that the proposed method improves both intelligibility and naturalness in various environments, whereas a function parameter can control the performance trade-off between intelligibility and naturalness.

• Journal of the Korean Solar Energy Society
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• v.26 no.3
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• pp.33-43
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• 2006

Daylight dimming control system was analyzed for an indirect lighting system in a small office space with a double skin envelope system. Computer simulations were performed for photosensors with three shielding conditions. The photosensors were placed on the center of ceiling, and backwall. Three sky conditions defined by CIE were considered. Overall, control performance was not very excellent for all conditions. Fully-shielded photosensor achieved good control performance for some cases, but partially-shielded and unshielded photosensors failed to achieve target illuminance. The variation in desktop illuminance due to daylight was examined for a variety of daylight conditions. Linear correlation between desktop illuminance and photosensor illuminance was analyzed using ANOVA.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.148.3-148
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• 2001

This paper deals with a problem of decreasing the airspeed and the altitude of a transport aircraft using thrust only. Such a situation can occur, if the aircraft loses all hydraulic power that drives the control surfaces. A controller for flight path angle control is designed using the model following servo control method, which is a PI-type optimal regulator. For computer simulation, a simulation model that covers a range of flight envelope is made using given linear models and trim points at some flight conditions. Nondimensional aerodynamic coefficients, derivatives and trim points that are not at the given trim points are computed by linear interpolation. The model is effective in simulation where the trim point varies. Simulation using ...

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.7
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• pp.632-641
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• 2000

The present study concerns the simulation of supply-air control in a variable air volume (VAV) system. A stratified lumped thermal model (multi-zone model) is suggested to predict local thermal response of an air-conditioned space. The effects of various thermal parameters such as the cooling system capacity, the thermal mass of air-conditioned space, the time delay of thermal effect, and the building envelope heat transmission are investigated in detail. Further, the influence of control parameters, PI control factor and the sensor location on a VAV system is quantitatively delineated. The results obtained show that the previous homogeneous lumped thermal model (1-zone model) may predict a significantly different thermal response in the air-conditioned space according to the sensor location.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.35-41
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• 2006

This paper proposes an algorithm for switching LQ(Linear Quadratic) controllers designed at each flight envelope without a bump phenomenon. This algorithm is derived to apply to LQ controller more easily than existing implementation algorithm and is proposed to consider trim points of nonlinear models, which is adequate to real applications. This paper exemplifies the control performance improvement via simulations applied to LQ control of a supersonic test aircraft as a benchmark problem to test the proposed algorithm performance.

• Structural Engineering and Mechanics
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• v.32 no.1
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• pp.179-191
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• 2009

A stochastic response spectrum method is proposed for simple evaluation of the structural response of an actively controlled aseismic structure. The response spectrum is constructed assuming a linear structure with an active mass damper (AMD) system, and an earthquake wave model given by the product of a non-stationary envelope function and a stationary Gaussian random process with Kanai-Tajimi power spectral density. The control design is executed using a linear quadratic Gaussian control strategy for an enlarged state space system, and the response amplification factor is given by the combination of the obtained statistical response values and extreme value theory. The response spectrum thus produced can be used for simple dynamical analyses. The response factors obtained by this method for a multi-degree-of-freedom structure are shown to be comparable with those determined by numerical simulations, demonstrating the validity and utility of the proposed technique as a simple design tool. This method is expected to be useful for engineers in the initial design stage for structures with active aseismic control.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.1
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• pp.74-80
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• 1996

This paper describes current controlled PWM technique of PM synchronous motors for a wide variety of speed control applications. They are however limited in their ability to operate in the power limited regime where the available torque is reduced as the speed is increased above its base value. This paper reviews the operation of the PMSM drives when they are constrained to be within the permissible envelope of maximum inverter voltage and current to produce the rated power and to provide this with the highest attainable rotor speed. The optimal field-weakening control algorithm is the use of phase current and d-axis current feedback to reduce of error between the d-axis current command and real current and to improve the torque characteristics. The improved torque characteristics of speed control strategy with optimal field weakening control algorithm is analyzed and the performance is investigated by the computer simulation and experimental results. (author). refs., figs.

• KIEAE Journal
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• v.15 no.3
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• pp.15-20
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• 2015

Purpose: Suggesting a working prototype of a kinetic light shelf unit and revealing its energy efficiency by a series of building performance simulations were presented. Recently, kinetic building envelope has been an emerging technology as an innovative way to control exterior building environment, but products from many researches about the facade could not been reached to the industrialization so far. That is because its initial installation, operation and maintenance costs are still too high to use for the practical field, although buildings using kinetic envelopes could decrease their energy consumption significantly. This narrow point of view needs to be reconsidered, since buildings require great amount of energies to run their functions through the whole life and using better building components can lead to achieve much more benefits in aspects of the lifecycle cost (LCC). Method: A series of certified simulation tools like Ecotect and Green Building Studio that are normally used for researches and developments in the field of architecture were utilized. Result: Based on simulation analyses, the result of the study has showed that the proposed system definitely has adaptability to the professions and positively shows practicability as advanced integrative building envelopes with renewable energy association.