• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1016-1020
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• 2001

The spinning is a very effective manufacturing technology for short production runs in a variety of sizes and shapes, because it can form the cross-section or tubular parts various shapes. However extensive experimental and analytical research has not been carried out. In this study, and fundamental experiment was conducted to improve productivity with process parameter such as tool path, angle of roller holder(a), feed rate(v) and corner radius of forming roller(Rr). These factors were selected as variables in the experiment because they were most likely expected to have and effect on spring back. The clearance was controlled in order to achieve the precision product which is comparable to deep drawing one. And also thickness and diameter distribution of a multistage cup obtained by shear spinning process were observed and compared with those of a commercial product produced by conventional deep drawing.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.4
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• pp.277-282
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• 2002

This paper proposes a nonlinear adaptive controller based on back-stepping method for tracking reference substrate concentration by manipulating dilution rate in a continuous baker's yeast cultivating process in stirred tank bioreactor. Control law is obtained from Lyapunov control function to ensure asymptotical stability of the system. The Haldane model for the specific growth rate depending on only substrate concentration is used in this paper. Due to the uncertainty of specific growth rate, it has been modified as a function including the unknown parameter with known bounded values. The substrate concentration in the bioreactor and feed line are measured. The deviation from the reference is observed when the external disturbance such as the change of the feed is introduced to the system. The effectiveness of the proposed controller is shown through simulation results in continuous system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11C
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• pp.75-84
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• 2001

In this paper, we propose an on-line FDD(Fault Detection and Diagnosis) system based on the three layer feed-forward neural network which is trained by the back-propagation teaming algorithm. We implement the on-line fault detection and diagnosis system by Visual C++ and Visual Basic. The proposed FDD system is applied to an air handling unit in operation. Experimental results show the high performance of our system in the task of fault detection and diagnosis.

• Journal of the Korea Society of Computer and Information
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• v.5 no.4
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• pp.112-119
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• 2000

In this paper, it aims at two different situation such that a preventive control which means, it never has network information in case of occurring congestion in network, and a reactive control which means, after the congestion simply happens. it is not effective to recover with congestion just because of extensive delay for an electric wave. To solve the problems, threshold is set up with buffer in multiplex system, and executes a congestion control by FBLB which is FeedBack Leaky Bucket Algorithm. As suggested by FBLB Algorithm. the outcome of performance could be compared with Buffered Leaky Bucket Algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.1
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• pp.46-51
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• 2006

We present simulation results for a method designed to extract key parameter values of DFB-type LDs based on ASE spectrum measurements. Comparisons were made between the given (actual) and the extracted (estimated) parameters, as well as the associated spectra, fur a variety of DFB-type LDs, and the two sets of results were found to be in excellent agreement.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.465-470
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• 2007

This paper is designed and producted the microstrip patch antenna which used aperture coupled feed structure, and had a comparatively hish gain and headband characteristic with a PCS substitution repeater antenna. The proposed antenna transformed a coupled slot into a H-type in order to improve a characteristic of a general aperture coupled feed antenna. It is this H-type form slot reduces back lobe from the antenna backside at the same time that a coupling between a power feed and patches is iccreased, and to have maximized a gain of an antenna. As a result of having measured the antenna which the VSWR was 1.5 or below and tied up the gain than 7.5dBi in the $1750{\sim}1870$[MHz] that was a PCS substitution, and a beamwidth became in $80^{\circ}$ and radio waves shadow was local, but accomplishment did PCS mobile communication service in building me smoothly, but confirmed what practical use can become.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.9
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• pp.186-191
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• 2001

Spinning process is a chipless metal forming method for axi-symmetric parts, which is more economical, efficient and versatile method for producing parts than the other sheet metal forming process such as stamping or deep drawing. In this study, a fundamental experiment was conducted to improve productivity with process parameters such as tool path, angle of roller holder($\alpha$), feed rate($\gamma$) and corner radius of forming roller(Rr). These factors were selected as variables in the experiment because they were most likely expected to hale an effect on spring back. The empirical results were analyzed to know how much spring back was affected by these factors. And also thickness and diameter distribution of a multistage cup obtained by spinning process were observed and compared with those of a commercial product produced by conventional deep drawing.

• Membrane and Water Treatment
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• v.10 no.2
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• pp.155-163
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• 2019

The roles of polypropylene (PP) beads and pH on membrane fouling and treatment efficiency were investigated in a hybrid advanced water treatment process of tubular carbon fiber membranes (ultrafiltration (UF) or microfiltration (MF)) and PP beads. The synthetic feed including humic acid and kaolin flowed inside the membrane, and the permeated contacted the PP beads fluidized in the space between the membrane and the module with UV irradiation and periodic water back-flushing. In the hybrid process of UF ($0.05{\mu}m$) and PP beads, final resistance of membrane fouling ($R_f$) after 180 min increased as PP beads increased. The turbidity treatment efficiency was the maximum at 30 g/L; however, that of dissolved organic matters (DOM) showed the highest at PP beads 50 g/L. The $R_f$ strengthened as pH of feed increased. It means that the membrane fouling could be inhibited at low alkali condition. The treatment efficiency of turbidity was almost constant independent of pH; however, that of DOM showed the maximum at pH 5. For MF ($0.1{\mu}m$), the final $R_f$ was the minimum at PP beads 40 g/L. The treatment efficiencies of turbidity and DOM were the maximum at PP beads 10 g/L.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.126-127
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• 2010

• Asian-Australasian Journal of Animal Sciences
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• v.7 no.3
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• pp.441-448
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• 1994

Postweaning performance data were obtained on 187 group fed purebred Angus calves from 12 selected sires (six high and six low feed conversion sires) in 1985 and 1986. The objective of this portion of the study was to develop prediction equations for feed conversion from a stepwise regression analysis. Variables measured were on-test weight (ONTSTWT), on-test age (ONTSTAG), five weights by 28-d periods, seven linear body measurements: heart girth (HG), hip height (HH), head width (HDW), head length (HDL), muzzle circumference (MC), length between hooks and pins (HOPIN) and length between shoulder and hooks (SHHO), and backfat thickness (BF). Stepwise regressions for maintenance adjusted feed conversion (ADJFC) and unadjusted feed conversion (UNADFC) over the first 140 d of the test, and total feed conversion (FC) until progeny reached 8.89 mm of back fat were obtained separately by conversion groups and sexes and for combined feed conversion groups and sexes. In general, weights were more important than linear body measurements in prediction of feed utilization. To some extent this was expected as weight is related directly to gain which is a component of feed conversion. Weight at 112 d was the most important variable in prediction of feed conversion when data from both feed conversion groups and sexes were combined. Weights at 84 and 140 d were important variables in prediction of UNADFC and FC, respectively, of bulls. ONTSTWT and weight at 140 d had the highest standardized partial regression coefficients for UNADFC and ADJFC, respectively, of heifers. Results indicated that linear measurements, such as MC, HDL and HOPIN, are useful in prediction of feed conversion when feed in takes are unavailable.