• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.78-91
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• 2005

Performance limiting factors (PLFs) derived from 161 drinking water treatment plants (DWTPs), assessed by International Technical Diagnosis & Assistance Center, were analyzed and evaluated in more detail in this study. In order to conduct study, 161 DWTPs were divided into five categories depending on their capacity, and into twelve groups according to processes and facilities. From the results of analysis, PLFs and their distribution ratio derived from each category were significantly different. Filtration was the most important performance limiting process in all DWTPs of five categories, and the PLFs in filtration were backwashing velocity, media configuration, bed depth, and formation of mud-ball. The PLFs in coagulation-flocculation process were found out to be coagulant dosage, mixing speed, mechanical problems, and others in the order of frequency of occurrence. Also, insufficient disinfection ability that is resulted from insufficient hydraulic detention time and improper chlorine dose and injection point, is the most significant among PLFs in a clear well. In the case of sedimentation, inappropriate baffle structure and excessive upward velocity were PLFs. In addition, the results showed that high turbid water and low alkalinity in a rainy season, ferric and manganese ions, and ammonia nitrogen have been contributed significantly on the performance of DWTPs.

• Journal of environmental and Sanitary engineering
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• v.16 no.2
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• pp.38-46
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• 2001

In this work, the heterogeneous ion exchange membrane was used in a electrodialysis apparatus to treat a Ni planting rinse water because the heterogeneous ion exchange membrane was excellent efficiency as compared with low manufacturing cost, was easy to make, and had a good mechanical properties. For a regeneration of membrane and to obtain the optimal condition for a scale-up of apparatus after treating Ni plating rinse water, we would find about the limiting current density and the concentration polarization. When the Ni plating rinse water 150mg/L was treated with the electrodialysis apparatus using the heterogeneous ion exchange membrane, the limiting current density was about $1.49{\;}mA/\textrm{cm}^2$. And the limiting current density increased with the flow rate and concentration of Ni plating rinse water. We recognized that the used membrane could be reused by periodic backwashing because efficiency was constant when the membrane was backwashed after treating wastewater.

• Applied Biological Chemistry
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• v.19 no.3
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• pp.162-171
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• 1976

The determination of rate limiting step in the metabolic process is of great importance to understand the metabolic properties. In this paper the authors propose a modified enzymatic method instead of thermodynamic method. This method is based on the assumption that the over-all rate increment would be larger than by any other steps to which the individual enzyme are added respectively, provided that the enzyme participated in the rate limiting step is added to the reactions composed of n steps of metabolic process with which n kind of enymes are concerned. The present paper deals with analysis and discussion about some factors having influence on the proposed process, mainly about the metabolic process constituted with homogeneous steps. The results show that the determination of rate limiting step by a modified enzymatic method is feasible, provided that some restrictions are added in any type of mechanisms.

• Journal of the Korean Statistical Society
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• v.36 no.4
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• pp.471-477
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• 2007

In this paper, we provide a new proof to correct the asymptotic normality for the estimate $\hat{C}_{pmk}\;of\;C_{pmk}$, which is one of the well-known definitions of the process capability index. Also we comment briefly on the correction of the limiting distribution for $\hat{C}_{pmk}$ and on the use of re-sampling methods for the inference of $C_{pmk}$. Finally we discuss the concept of asymptotic unbiasedness.

• Journal of environmental and Sanitary engineering
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• v.11 no.3
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• pp.63-68
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• 1996

This study was to discuss limiting factors influenced on the removal efficiencies of nitrogenous compounds investigated using the polypropyrene media which was to attach microorganism in order to apply the fixed-biofilm process. The main limiting factors are the hydraulic retention time (HRT), C/N ratio, $COD/NO_{3}-N$ ratio and temperature. The hydraulic retention time HRT were 6, 8, 10, 12 hrs and the C/N ratio range was 2.5-9.5. The $COD/NO_{3}-N$ ratio range was 3.2-21.9 and the temperature were 15, 20, 25, 30, $35^{\circ}C$, respectively. The results of this study are summerized as follows. 1. Hydraulic retention time (HRT) to obtain removal efficiencies of T-N higher than 85% had to be 10 hrs above. 2. The removal efficiencies of T-N decreased at C/N ratio from 6.2 to 4.8 in this anoxic-contact aeration system. 3. Denitrification rate decreased at $COD/NO$_{3}$-N$ ratio from 8.0 to 5.0 4. As temperature increased, removal efficiencies of T-N increased.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.4
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• pp.210-218
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• 2000

For the fabrication of $YBa_2Cu_3O_x$ thick film, a substrate of $Y_2BaCuO_5$ was fabricated by adding $CeO_2$ into $Y_2BaCuO_5$ and two types of doping materials added with binder material were prepared. Each doping material was patterned on $Y_2BaCuO_5$substrate by the screen printing method and then was annealed at the temperature with a few step. It could be observed by X-ray diffraction patterns and SEM photographs that through the diffusion process of the $Y_2BaCuO_5$ and each doping material, the $YBa_2Cu_3O_x$ phase was formed. And with n additive of $CeO_2$ the thickness of formed $YBa_2Cu_3O_x$decreased. From the experiment of current limiting on thick film, the sample with thiner thickness of $YBa_2Cu_3O_x$ showed the more effective characteristics of current limiting.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1451-1453
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• 1994

A monolithic current limiting power MOSFET, which may be easily fabricated by the conventional DMOS process, is proposed. The proposed current limiting MOSFET consists of main power cells, sensing cells, and NPN lateral bipolar transistor so that users can adjust the current limiting levels with only one external resistor. The behaviors of the proposed device are numerically simulated and analyzed by 2-D device simulator MEDICI and mixed-mode simulator CA-AAM(Circuit Analysis Advanced Application Module).

• Journal of the Korean Data and Information Science Society
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• v.28 no.3
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• pp.697-707
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• 2017

In this paper, we propose a modified GARCH(p, q)-X model which is obtained by adding the exogenous variables to the modified GARCH(p, q) process. Some limiting properties are shown under various stationary and nonstationary exogenous processes which are generated by another process independent of the noise process. The proposed model extends the GARCH(1, 1)-X model studied by Han (2015) to various GARCH(p, q)-type models such as GJR GARCH, asymptotic power GARCH and VGARCH combined with exogenous process. In comparison with GARCH(1, 1)-X, we expect that many stylized facts including long memory property of the financial time series can be explained effectively by modified GARCH(p, q) model combined with proper additional covariate.

• JSTS:Journal of Semiconductor Technology and Science
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• v.2 no.1
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• pp.87-92
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• 2002

We present a simple experimental method for determination of limiting intrinsic fixed-pattern non-uniformity (NU) due to fabrication process in two-dimensional CCD multiplexers (MUXs) that are used for hybrid focal plane arrays. Here, this is done by determining separately the two NUs viz. that are $V_T$ dependent and $V_T$ independent. From these measurements, process dependent NU can be extracted. It is argued that $V_T$ dependent NU can be eliminated by designing novel input circuits whereas $V_T$ independent NU, primarily, dependent on process control and material variations may be reduced but cannot be eliminated completely and hence limits the FPA performance eventually.

• Journal of the Korean Statistical Society
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• v.22 no.2
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• pp.307-324
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• 1993

The limiting distribution of the excess over the boundary is determined for the autoregressive process.