• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.731-739
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• 2015

In arrhythmia ECG signal, abnormal beat that has various abnormal shape depending on the generation site and conduction disorders is included and it is very important to diagnose heart disease such as arrhythmia. In this paper, we propose a PVC abnormal beat detection algorithm associated with ventricular disease. The PVC abnormal beat is characterized by distortion of the QRS complex occurs among the components of the ECG signal. Therefore it is possible to detect PVC abnormal beat according to the degree of distortion of the QRS complex. First, quantify the distortion of the QRS complex by using the potential of the R-peak, kurtosis and period. By using the mean and standard deviation, PVC abnormal beat is detected depending on the degree of distortion from the normal beat. The proposed algorithm can detect the average over 98% of the AAMI-V class type abnormal beat associated with ventricular disease in MIT-BIH arrhythmia database.

• Applied Microscopy
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• v.34 no.1
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• pp.51-59
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• 2004

The high acceleration voltage system used in scanning electron microscope were designed and manufactured to test its stability. The Cockcroft-Walton circuits are used both in the cathode voltage up to -30 kV and in the Wehnelt cylinder of -2 kV. The operating voltage of 6 V was applied to the heating of the filament. The wave forms which are formed in the second leg of the high voltage transformer were observed in the oscilloscope with 2 V of DC input. When the high voltages were in the range between 5 kV and 12 kV, the highest value of the stabilities of the generated voltages was obtained as 0.002%.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.28-39
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• 2018

In this study, numerical simulations were performed for steady and unsteady state characteristics of length effects on linear pintle nozzles using the overset grid method. Nozzles and pintles are created separately by an auto grid generation program to use the overset grid method. Appropriate turbulent models and numerical methods are selected for the validation of simulations. Pintle shapes are chosen from five types, with differences in the ratio of length and diameter. The longer the pintle length, the greater the thrust and thrust coefficient. The chamber pressure tendency of steady-state and unsteady-state are different for various pintle velocities. The thrust of the nozzle exit responds to changes in the nozzle throat in the unsteady-state, and the speed of pressure propagation wave generated by movement of the pintle is considered to predict the major factor of performance.

• Journal of Ginseng Research
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• v.31 no.3
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• pp.159-174
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• 2007

Pharmacology of Korean Red ginseng gives us unique possibility to develop new class of antiepileptic drugs today and to improve one's biological activity. The chemical structures of ginsenosides (GS) have some principal differences from well-known antiepileptic new generation drugs. The antiepileptic effect of GS was also demonstrated in all models of epilepsy in rats (young and adult), which have studied, in all models of epilepsy including status epilepticus (SE), induced by lithium - pilocarpine. In our experiments in rats new evidences on protective effects were exerted as a result of premedication by GS. Pre-treatment of several GS could induce decrease of the seizures severity and brain structural damage (by MRI), neuronal degeneration in hippocampus. Wave nature of severity of motor seizures during convulsive SE was observed during lithium-pilocarpine model of SE in rats (the first increase of seizures was 30 min after the beginning of SE and the second - 90 min after. The efficacy of treatment on SE by ginsenoside as expected was observed after no less 3 weeks by daily GS i.p. administration. It is blocked SE or significantly decrease the severity of seizures during SE. The implication of presented data is that combination of ginsenosides from Korean Red ginseng and ginseng cell culture Dan25 that could be applied for prevention of epileptical status development. However, a development of optimal ratio of different ginsenosides $(Rb_1$ Rc, Rg, Rf,) should consummate in the new antiepileptic drug development.

• The Korean Journal of Physiology
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• v.10 no.1
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• pp.41-48
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• 1976

Tetrodotoxin (TTX) is the purified active principle responsible for tetrodon (Puffer-fish) poisoning which has long been known in the Orient. The pharmacological actions of TTX have been rather extensively investigated. Two of the most prominent effects of intravenousely administered TTX are severe hypotension and respiratory paralysis resulting from its depressant actions on tissues. This depressant actions of TTX in turn result from the selective inhibition of sodium-carrying mechanism which is essential to generation of the action potential. TTX differs from local anesthetics in that it does not affect potassium conductance. Although the mechanism of the hypotensive action of TTX remains a subject of controversy, most investigator agree that TTX-induced hypotension is caused by alteration in the blood vessels rather than the heart. Not only the study on the effects of TTX on cardiac function is meager but the results of reported works are often contradictory. The present study was undertaken to investigate the effect of TTX on the electrocardiogram of the rabbit and to compare them with well known electrocardiographical characteristics found in digitalis and quinidine intoxicated animals. The results obtained from the present study are summarized as follows. 1. No changes were found in P-R interval and QRS duration after i.v. administration of $1.0\;{\mu}g/kg\;to\;1.5\;{\mu}g/kg$ TTX to the animals. It is obvious that there were no conduction disturbance between atria and ventricles as well as in the ventricular tissue. 2. In $1.0\;{\mu}g/kg$ TTX group, S-T interval and T-P segment were not changed whereas marked changes were observed in $1.5\;{\mu}g/kg$ TTX group. 3. The first and second degree A-V blocks appeared in the $2.0\;{\mu}g/kg$ TTX group. 4. TTX differs from digitalis and quinidine in that it does not cause S-T interval depression and T-wave inversion. In contrast with digitalis, TTX caused Q-T interval prolongation.

• Corrosion Science and Technology
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• v.9 no.1
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• pp.48-55
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• 2010

The many vessels are built with FRP(Fiber-Reinforced Plastic) material for small boats and medium vessels. However, FRP is impossible to be used for recyclable material owing to environmental problems and causes large proportion of collision accidents because radar reflection wave is so weak that large vessels could not detect FRP ships during the sailing. Hence, Al alloy comes into the spotlight to solve these kinds of problems as a new-material for next generation instead of FRP. Al alloy ships are getting widely introduced for fish and leisure boats to save fuel consumption due to lightweight. In this study, it was selected 6061-T6 Al alloy which are mainly used for Al-ships and carried out various electrochemical experiment such as potential, anodic/cathodic polarization, Tafel analysis, potentiostatic experiment and surface morphologies observation after potentiostatic experiment for 1200 sec by using the SEM equipment to evaluate optimum corrosion protection potential in sea water. It is concluded that the optimum corrosion protection potential range is -1.4 V ~ -0.7 V(Ag/AgCl) for 6061-T6 Al alloy, in the case of application of ICCP(Impressed current cathodic protection), which was shown the lowest current density at the electrochemical experiment and good specimen surface morphologies after potentiostatic experiment for Al-Mg-Si(6061-T6) Al alloy in seawater environment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.58-68
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• 1998

A computer-controlled system for measuring dielectric hysteresis has been developed. This system consists of the wave generation par\, the high voltage amplifier part, the measurement part, the data acquisition part and the related controll circuits and is interfaced to P.C(personal computer). The applied voltage and its frequency are controlled by P.C . Since the measured datas can be saved in the RAM of P.C, the analysis and the graphics of the datas are very convenient. As a accuracy test, the capcitances of the commercial mica and styroll capacitors were measured by applying high voltage and the results were good agreement with the rating values. In the test of PZT ceramic sample, the typical D-E hysteresis loops were obtained by applying a single frequency voltage to the sample, and $\varepsilon-E$ and D-E hysteresis loops could be measured at the same time by applying a double frequency voltage to the sample.sample.

• Archives of design research
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• v.17 no.3
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• pp.123-132
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• 2004

This paper shows a study on the "Korean High Speed Train Design" method, its design process and the result in the form of aerodynamic optimal exterior design development of a prototype test train(HSR 350${\times}$). It was developed from 1996 until 2002, six years long in R '||'&'||' D project titled "Development of High Speed Railway Technology" The end result of the project is a prototype test train, which has two power cars, two motorized trailers and three trailers, had been tested successfully in the year 2003 to the highest speed limit 380km/h on high speed line. The improved conceptual design work of a new commercial train and next generation's train is also performed for future needs.uture needs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.1824-1831
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• 2009

This paper analyzes the propagation speed of the wide-area power system frequency. When a generator supplying the electric power to the grid is accidently tripped due to a disturbance on the systems, power system frequency suddenly drops during the transient period and this propagates from the location of the tripped generator to the other part of the systems like a wave. Since the propagation speed of the power system frequency depends on the own characteristics of power systems, its understanding from the perspective of the wide-area can help us in understanding power systems more correctly. In addition, the propagation speed of the power system frequency is used as a key parameter in the application study of IT based on the internet-based GPS synchronized frequency monitoring network (FENT) which has been recently implemented and operated in U.S. power systems. This paper simulates the generation trip on various locations in U.S. power systems deploying its latest dynamic model and calculates the propagation speed of the power system frequency for the application of FNET.

• Nuclear Engineering and Technology
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• v.39 no.3
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• pp.193-206
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• 2007

The Korea Atomic Energy Research Institute has developed an advanced fast reactor concept, KALIMER-600, which satisfies the Generation IV reactor design goals of sustainability, economics, safety, and proliferation resistance. The concept enables an efficient utilization of uranium resources and a reduction of the radioactive waste. The core design has been developed with a strong emphasis on proliferation resistance by adopting a single enrichment fuel without blanket assemblies. In addition, a passive residual heat removal system, shortened intermediate heat-transport system piping and seismic isolation have been realized in the reactor system design as enhancements to its safety and economics. The inherent safety characteristics of the KALIMER-600 design have been confirmed by a safety analysis of its bounding events. Research on important thermal-hydraulic phenomena and sensing technologies were performed to support the design study. The integrity of the reactor head against creep fatigue was confirmed using a CFD method, and a model for density-wave instability in a helical-coiled steam generator was developed. Gas entrainment on an agitating pool surface was investigated and an experimental correlation on a critical entrainment condition was obtained. An experimental study on sodium-water reactions was also performed to validate the developed SELPSTA code, which predicts the data accurately. An acoustic leak detection method utilizing a neural network and signal processing units were developed and applied successfully for the detection of a signal up to a noise level of -20 dB. Waveguide sensor visualization technology is being developed to inspect the reactor internals and fuel subassemblies. These research and developmental efforts contribute significantly to enhance the safety, economics, and efficiency of the KALIMER-600 design concept.