• Clinical and Experimental Reproductive Medicine
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• v.20 no.2
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• pp.107-115
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• 1993

Procedures to separate motile. normal & motile and acrosome-reacted sperm with high efficiency have clinical application in Assisted Reproductive Technology in terms of increasing the probability of fertilization by a normal sperm and subsequent normal embryonic development. This study evaluated the effects of 10 sperm preparation techniques [Swim-up from a washed pellet (SU). Swim-up from semen (SO). Continuous Percoll Gradients I (PIC). Discontinuous Percoll Gradients I (PID). Continuous Percoll Gradients II(P II C). Discontinuous Percoll Gradients II(P II D), SpermPrep (SFC). Wang's tube (WT). Albumin Gradients (AG), Low temperature capacitation (LTC)] on motility (%), normal morphology (%), motile sperm recovery rate(%). morphologically normal & motile sperm recovery rate (%), true acrosome reaction (%) and fertilizing ability. A P II D proved to be an effective means of separating morphologically normal & motile sperm. Our results indicated the P II D has advantages as compared with other methods in terms of recovery rate. enhancement of motility and normal morphology. And a LTC seems to be an effective means of enhancing the true acrosome reaction and fertilizing ability. These results suggest that the combined method of LTC and P II D for separation of morphologically normal & motile sperm and acrosome reacted sperm may be a useful procedure for intrauterine insemination and in vitro fertilization in the management of male factor infertility as well as for isolation of subpopulation of sperm for basic research.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.62-73
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• 2014

This research was focused to apply response surface methodology for optimization of bio-methane production by biogas upgrading process. Methane concentration(Y1) and methane efficiency(Y2) on biogas upgrading process were mathematically described as being modeled by the use of the Box-Behnken design on response surface methodology. The results of ANOVA(analysis of variance) about models, the probability value of the methane concentration and methane recovery response surface model are 0.0001 and 0.0001, respectively and coefficient of determination($R^2$) are 0.9788 and 0.9710, respectively. The response surface model is proved of high reliability and suitability. The operation pressure had the greatest influence to methane concentration than other operation parameters and the PSA rotary valve velocity had the greatest influence to methane recovery than other operation parameters. Optimal condition of biogas upgrading process for production of $100Nm^3/hr$ bio-methane were operation pressure 8.0bar and outlet flow rate 31.55RPM, respectively. At that operation condition the methane concentration of bio-methane was 97.13% and methane recovery in biogas upgrading process was 75.89%.

• Journal of Veterinary Clinics
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• v.8 no.1
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• pp.81-91
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• 1991

This study was carried out to investigate the effects of intravenous drip with ketamine hydrochloride and its application for control depth and maintenance of anesthesia in dogs. Changes of blood pressure, vital signs, blood gas and anesthetic state were observed in this study. The obtained were summerized as follows ; 1. Changes of blood pressure and heart rate after intravenous drip anesthesia with ketamine hydrochloride were observed with significant increase in all group ; group II (0.135m81k9/min), group III (0.269mg/kg/min) and group IV(0.538mg/kg/min). These conditions were maintained unchangeably until 160 minutes after administration in all group. This may be indicated that there were no side effects on account of ketamine accumulation. 2. There were irregular respiration, pain reflex, Jaw tone reflex and vomition probability in the anesthetic conditions of group II The anesthetic conditions of group III were rarely shown as mentioned above. Awakening time and recovery time of group H were more prolonged 21 minutes and 27 minutes respectively than those of group III. These experimental data suggested that the optimal dosage of intravenous drip anesthesia of ketamine Hcl was 0.269mg/kg/min.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.476-484
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• 2009

This paper deals with improvements to the special protection schemes (SPS) which have been applied to the low probability and high impact contingencies in the Korea Electric Power Corporation (KEPCO) system since 2004. Among them, the SPS for voltage instability in the Seoul metropolitan area is considered in this paper, and is a form of event-based undervoltage load shedding with a single-step scheme. Simulation results based upon a recent event that occurred on 765kV lines show that the current setting values of the SPS have to be revised and enhanced. In addition, by applying response-based multi-step undervoltage load shedding (UVLS) schemes to severe contingencies in the system, more effective results than those of the existing single-step SPS can be obtained. Centralized and distributed UVLS schemes are considered in the simulation. ULTC-based load recovery models and over excitation limiters (OXL) for the KEPCO system are also included in the long-term voltage instability studies.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.3
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• pp.83-88
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• 2012

This paper studies the effects of wavelength conversion on self-healing optical networks. We examined the effects of wavelength conversion capability on the backup routing and the spare wavelength utilization. The efficiency of spare wavelength utilization is proportionally increased as the wavelength conversion capability increases, different from the call blocking probability for which about 30% of wavelength conversion capability shows nearly the same performance as full wavelength conversion capability. The spare resource utilization efficiency can be improved by using alternate routing and wavelength assignment algorithms.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.520-524
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• 2009

In compressed color images, colors are usually represented by luminance and chrominance (YCbCr) components. Considering characteristics of human vision system, chrominance (CbCr) components are generally represented more coarsely than luminance component. Aiming at possible recovery of chrominance components, we propose a model-based chrominance estimation algorithm where color images are modeled by a Markov random field (MRF). A simple MRF model is here used whose local conditional probability density function (pdf) for a color vector of a pixel is a Gaussian pdf depending on color vectors of its neighboring pixels. Chrominance components of a pixel are estimated by maximizing the conditional pdf given its luminance component and its neighboring color vectors. Experimental results show that the proposed chrominance estimation algorithm is effective for quality improvement of compressed color images such as JPEG and JPEG2000.

• Journal of Korea Foundry Society
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• v.2 no.3
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• pp.16-24
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• 1982

For the purpose of development of domestic carburizer, when the basicity of ash in carburizer was changed from $Na_2O/Al_2O_3+SiO_2$ ; 0.06 to $Na_2O/Al_2O_3+SiO_2$ ; 0,196wt%, using $Na_2O$ as flux for domestic graphite resource (Bong Myung armorphous graphite), carburizing efficiency was improved as basicity increased, optimum basicity value was $Na_2O/Al_2O_3+SiO_2$ ; 0.151. This means that $Na_2O$ contributed to lower viscosity of slag and raise occurence probability of specific reaction surface between molten iron and carburizer. The experiment of effect of general characteristics offecting carburizing ability of this carburizer was performed, the result is that 10/30 mesh was optimum size of the carburizer and as carbon equivalent of molten iron was higher, carburizing ratio was lowered, but when si concentration was below 1.8% in general cast iron melting region, recovery showed 75-85%. As agitation rate of molten iron and temperature interval were higher, Carburizing ratio was increased and showed max, 94%. Desulfurizing phenomena of molten iron by $Na_2O$ in carburizer didn't appear.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.422-428
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• 2011

Optimal reliability indices were found by optimizing life cycle cost(LCC) of pier type quay walls. Failure probability of pier and shore bridge were calculated by response surface method. Then, they were used to obtain recovery cost after damage. Costs for initial construction and maintenance were also considered in finding optimal reliability indices. Target reliability indices which may be used in reliability based design were suggested by numerical examples under seismic load and ship load.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.1
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• pp.38-46
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• 1992

In this thesis, a high speed code synchronization circuit is implemented, which is applicable to frequency hopping FSK tranceiver within 68-88 MIBz band- width. synchronization Process consists of two steps, initial synchronization and tracking. A modified matched filter method using two channel passive correlators matched with short hopping frequencies, synchronization prcfix. is proposed for initial synchronization. To increase probability of initial synchronization, prefix are transmitted repeatedly. The outputs of correlators are sent to synchronization decision circuit, and code start time Is extracted by synchronizatlon decision circuit-Modified matched fitter method makes it possible to reduce complexity in hardware and obtain code acquisition rapidly.Clock recovery circuit regenerates PN code clock for tracking.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.1-11
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• 2016

We investigate compressive sensing techniques to estimate sparse channel in Orthogonal Frequency Division Multiplexing(OFDM) systems. In the case of large channel delay spread, compressive sensing may not be applicable because it is affected by length of measurement vectors. In this paper, we increase length of measurement vector adding pilot information to OFDM data block. The increased measurement vector improves probability of finding path delay set and Mean Squared Error(MSE) performance. Simulation results show that signal recovery performance of a proposed scheme is better than conventional schemes.