• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.4
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• pp.322-331
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• 1988

In this thesis, an active RC filter using high order inverse chebyshev function is designed and the design method for cascading blocks with low sensitivity and maximum dynamic range is discussed. To have maximum dynamic range, we have proposed the simple algorithm with a pole-zero pairing, the cascading sequence by flatness matrix and optimum gain distribution for a given transfer function. And 2nd order Block is designed with negative feedback to improve the sensitivity problem which had a defect at active RC circuits. Using the suggested method, we have designed the active RC low pass filter of the normalized 7th order inverse chebyshev function, as a results, we have shown that this accord with the given specification.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.149-159
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• 1998

The importance of soundness and safety evaluation in weld zone using by the ultrasonic wave has been recently increased rapidly because of the collapses of huge structures and safety accidents. Especially, the ultrasonic method that has been often used for a major non-destructive testing(NDT) technique in many engineering fields plays an important role as a volume test method. Hence, the defecting any defects of weld Bone in austenitic stainless steel type 304 using by ultrasonic wave and neural network is explored in this paper. In order to detect defects, a distance amplitude curve on standard scan sensitivity and preliminary scan sensitivity represented of the relation between ultrasonic probe, instrument, and materials was drawn based on a quantitative standard. Also, a total of 93％ of defect types by testing 30 defect patterns after organizing neural network system, which is learned with an accuracy of 99％, based on ultrasonic evaluation is distinguished in order to classify defects such as holes or notches in experimental results. Thus, the proposed ultrasonic wave and neural network is useful for defect detection and Ultrasonic Non-Destructive Evaluation(UNDE) of weld zone in austenitic stainless steel 304.

• Geosystem Engineering
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• v.21 no.6
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• pp.335-343
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• 2018

Alkali-surfactant polymer flooding has become an important technique to improve oil recovery following the development of oil fields while the function of emulsification in enhanced oil recovery is rarely considered in the existing mathematical model for numerical simulation. In this paper, the mechanism of improving the recovery of the emulsification was analyzed in ASP flooding, and a relatively perfect mathematical model with deep filtration-theory was established, in which oil-water volume equation, saturation equation, viscosity equation, and permeability reduction equation are included. The new model is used to simulate the actual block of an oil field; the simulated results of the new model and an old model without considering the emulsification are compared with the actual well history. It is found that new model which is easy to be realized in numerical simulation has a high precision fitting, and the effect of adding oil and decreasing water is obvious. The sensitivity of emulsification was analyzed, and the results show that the water reducing funnel becomes wider and the rate of water cut decreases rapidly with the increase of emulsifying capacity, and then the rate of recovery slows down. The effect of increasing oil and decreasing water is better, and the degree of recovery increases. The emulsification of the ASP flooding is maintained at a moderate level, which corresponds to ${\Phi}=0.2$ in the new model, and the emulsification is applied to realize the general mathematical quantitative description, so as to better guide the oilfield development.

• Journal of Chest Surgery
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• v.9 no.2
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• pp.265-270
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• 1976

Implantation of a permanent pacemaker is a widely accepted procedure for the patient with complete heart block.As a result of these device, the prognosis for patients with Adams-Stokes syndrome caused by complete A-V block and other cardiac arrhythmia have become much more optimistic. Permanent pacemaker implantation by means of a transvenous approach has made the operative risk much less and the procedure simpler. However, a number of complications have been reported in the literature regarding transvenous endocardial pacemaker implantation during the last a decade. The patient presented in this paper is a 26-year old girl who was implanted with a permanent pacemaker at 14 years of age because of a congenital A-V block. Following first exchange of pulse generator, the electrode (lead) was fractured, so that by the pulse generator, a change to the transvenous technique of implantation was made, After this, there were episodes of recurrent wound infection on three occasions, even though the site of pulse generator implantation was exchanged to the contralateral side of chest wall, massive doses of antibiotics were administered and sensitivity tests for coagulase positive staphylococcal infection were performed. Though there was no definite evidence of blood stream infection by blood culture, we decided not to use the transvenous technique and not to implant the pulse generator in the chest wall because the venous system and the entire anterior chest wall appeared to be diseased or contaminated by virulent pyogenic organisms. Finally this intractable systemic and local wound infection was successfully controlled by myocardial lead implantation via a subxiphoid approach and implantation of the pulse generator far down in the abdominal wall. The causes and routes of recurrent wound infection and possible blood born infection in this particular patient are still obscure. We strongly believe that myocardial pacemaker implantation is much safer than transvenous endocardial pacemaker implantation & myocardial pacemaker implantation is a definite method for controlling such an intractable wound infection. following transvenous pacemaker implantation.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1219-1224
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• 2004

The objective of this study is to propose an experimental calibration facility in which a heat flux sensor can be calibrated under conductive condition by using helium gas. The heat flux calibration facility was designed, simulated and manufactured for use in a high heat transfer condition. It delivers heat fluxes up to a maximum of 35 KW $m^{-2}$. A copper block heated electrically with 3.5 KW power is designed to produce uniform temperature up to 600 K across its face. High heat fluxes are provided between hot plate and cold plate by 1 mm height helium filled gap. A cold plate is maintained around 300 K through pool boiling using a refrigerant and water-cooled heat exchanger. A simulation was conducted to verify the design of the main test section. To verify the performance of calibration facility, a heat flux sensor was examined. The measured heat fluxes were compared to the calculated one.

• Journal of the Korean Operations Research and Management Science Society
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• v.33 no.2
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• pp.75-86
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• 2008

A remarshalling is one of the operational strategies considered importantly at a port container terminal for the fast ship operations and heighten efficiency of slacking yard. The remarshalling rearranges the containers scattered at a yard block in order to reduce the transfer time and the rehandling time of container handling equipments. This Paper deals with the rearrangement problem, which decides to where containers are transported considering time value of each operations. We propose the mixed integer programming model minimizing the weighted total operation cost. This model is a NP-hard problem. Therefore we develope the heuristic algorithm for rearrangement problem to real world adaption. We compare the heuristic algorithm with the optimum model in terms of the computation times and total cost. For the sensitivity analysis of configuration of storage and cost weight, a variety of scenarios are experimented.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.3
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• pp.67-78
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• 1990

A decision support system, Daily Irrigation Network Operation Simulation model (DINOPS) was developed that can adequately describe the physical behavior of an irrigation system. The model is to depict the physical features of complex water allocation schemes of the irrigation system and to simulate the response of the system to different irrigation schemes. The model was validated on the Banweol irrigation district by comparing the simulated canal discharges and paddy water levels with the field data. The operation of the DINOPS model was demonstrated on the irrigation district where several irrigation management practices were evaluated with computing irrigation efficiencies and rainfall effectiveness respectively. The model sensitivity with respect to heights of bund and block diversion rates were analyzed and discussed.

• Journal of Magnetics
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• v.13 no.1
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• pp.34-36
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• 2008

For the measurement of the magnetic field distribution with high spatial resolution and high accuracy, the magnetic field sensing probe must be non-magnetic, but the MFM probe and sub-millimeter-meter size Hall probe use a ferromagnetic tip and block, respectively, to increase the sensitivity. To overcome this drawback, we developed a micro-size search coil magnetometer which consists of a single turn search coil, Terfenol-D actuator, scanning system, and control software. To reduce the noise generated by the stray ac magnetic field of the actuator driving coil, we employed an even function $\lambda$-H magnetostriction curve and lock-in technique. Using the developed magnetometer, we were able to measure the magnetic field distribution with a magnetic field resolution of 1 mT and spatial resolution of $0.1mm{\times}0.2mm$ at a coil vibration frequency of 1.8 kHz.

• Speech Sciences
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• v.12 no.2
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• pp.43-56
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• 2005

This study was analyzed the syllable structure of Korean and Chinese using subjective sound similarity judgement tasks with both Korean-chinese and Chinese students in Shenyang, China. 86 college students were administered with the tasks which lasted about 20 min. in a small group setting. Both Korean-chinese and Chinese students showed the sensitivity for the CV sub-syllabic unit and the CV+C was the building block for phonetic representation for both languages. This syllabic similarity of Korean and Chinese may be a help for Korean-chinese to become horizontal bilinguals. Further studies are needed to specify the mechanism that will explain the syllabic perception of CV+C in both Korean and Chinese which was different from that of C+VC structure dominance in English.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.2
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• pp.76-84
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• 2006

Interstate electric power system, as an alternative for energy cooperation under regional economic block, has been hotly debated before progressing the restructure in electric power industry and rapidly expanded in many regions after 1990s. Especially, since northeast asia has strong supplementation in resource, load shape, fuel mix etc., interconnection of electric power systems in this region may bring considerable economic benefits. This paper implements a mathematical optimization model, ORIRES, proposed by Russia, in analysing the economic feasibility of system interconnection. Additional analyses on the environmental impact of the system interconnection, and sensitivity of key factor inputs have been performed.