• Journal of Electrical Engineering and Technology
• /
• v.12 no.5
• /
• pp.1697-1708
• /
• 2017

This paper proposes an algorithm for the differential protection of an Indirect Symmetrical Phase Shift Transformer (ISPST) by considering the different behaviors of the compensated differential current under internal fault and magnetizing inrush conditions. In this algorithm, a criterion function is defined which is based on the difference of amplitude of the wavelet transformation over a specific frequency band. The function has been used for the discrimination between three phase magnetizing inrush and internal fault condition and requires less than a quarter cycle after disturbance. This method is independent of any coefficient or threshold values of wavelet transformation. The merit of this algorithm is demonstrated by the simulation of different faults in series and excitation unit and magnetizing inrush with varying switching conditions on ISPST using PSCAD/EMTDC. Due to unavailability of in-field large interconnected transformers for such a large number of destructive tests, the results are further verified by Real Time Digital Simulator (RSCAD/RTDS). The proposed algorithm has been compared with the conventional harmonic restraint based method that justifies the application of wavelet transform for differential protection of ISPST. The proposed algorithm has also been verified for different rating of ISPSTs and satisfactory results were obtained.

• Journal of Ocean Engineering and Technology
• /
• v.10 no.4
• /
• pp.149-159
• /
• 1996

Multipurpose development of the coast and ocean can be considered as multifunction construction combining the functions of coastal protection, waterfront amenity and creation or rehabilitation of habitats. Multfunction development of coastal and ocean spaces can be accomplished by applying the ecosystem control structure of artificial habitats which will cultivate fishing ground with ecological harmony to the coastal protection system. To evaluate the applicability of ecosystem control structures as as fundamental coastal protection structure, wave control function of the structure is studied by numerical and physical analyses. Dimensional analysis and hydraulic experiment point out the importance of width and crest depth of ecosystem control structure, construction water depth and wave steepness. Wave control efficiency is estimated by the attenuation coefficient $(K_H)$ according to wave steepness $(H_0/L_0)$, relative constructed water depth $(h_i/H_0)$, relative berm width $(B/L_0)$ and relative crest depth $(h_B/H_0)$ of eosystem control structure. Empirical fomulas are suggested based on the results of model test by applying the multiple model based on this experimental results and numerical wave shoaling-dissipation-breaking model appears to be valid for the analysis of wave transformation around ecosystem control structure in the coastal waters.

• Journal of Chest Surgery
• /
• v.21 no.2
• /
• pp.246-253
• /
• 1988

An in vitro model providing with a recirculating perfusion apparatus using an isolated canine heart and its autogenous blood, which was prepared for study of myocardial protection method. This apparatus was easily used by quick connect system and maintained well heart function for about 2 hours. The Langendorff perfusion was initiated for a 10 minute period by introducing perfusate at 37` into the aorta from aortic reservoir located 100 cm above the heart. The isolated perfused working canine heart model was a left heart preparation in which oxygenated perfusion medium [at 37K] entered the cannulated left atrium at a constant flow rate [900ml/ min] under 20 mmHg overflow system and was spontaneously ejected[no electrical pacing] via an cannula against a hydrostatic pressure of 80 cm H2O. During this working period, various indices of cardiac function were measured. The cardiac functions were stable for over 2 hours with perfusion of Krebs-Henseleit solution and autologous blood[1:1] mixture in volume and maintained heart rate ]]3-122/bpm peak systolic pressure 109-113 mmHg, cardiac output 900 ml / min and left atrial mean pressure 8-9 mmHg. In this model, the efficiency of myocardia] protection could be easily measured by means of functional, enzymatic, biochemical and ultrastructural assessment. And also, we believe this model to be a useful assessment screening model of recovery state after long duration of myocardial preservation of donor heart without difficult transplantation procedures.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 1997.11a
• /
• pp.617-624
• /
• 1997

Over 100 experiments have been conducted at the University of Maryland to evaluate the performance of a water mist fire suppression system for protection of an interstitial space below a raised subfloor. Experiments are conducted as part of an ongoing research effort to compare the fire suppression capabilities of various water mist system designs in a raised subfloor space. Water mist system design parameters considered in the investigation include means of actuation, concentration of water mist required for extinguishment of fires, and delivery mechanisms of water mist within close proximity to the fire. Delivery of the required concentration of water mist within close proximity to the fire is a principal factor governing the adequacy of water mist systems. Two sets of experiments have been conducted to document the performance of water mist system designs. One set is involved in documenting the concentration of water mist as a function of position within the space. The second set of experiments is concerned with the ability of water mist system designs to control fires in the space. One result of the research is the assessment of the ability of a water mist system to control fires at particular locations as a function of water mist density at that location.

• Journal of Society of Preventive Korean Medicine
• /
• v.18 no.1
• /
• pp.11-21
• /
• 2014

Objective : This study set out to combine the treatment efficacy of Taraxacum with Dongchimi fermentation and investigate Taraxacum's effects on protection of liver cell and controlling nitric oxide(NO) through experiments, thus checking whether it had values as a physiological active matter. The experimental materials include Taraxacum Dongchimi (TD) and Taraxacum fermented by Dongchimi (TDF). As for methodology, experiments were carried out to compare TD and TDF in components, protection effects for liver cells, anticancer effects on liver cells, and protection effects for brain cells in the aspects of liver function and immunity enhancement. Method : The experimental materials include Taraxacum Dongchimi (TD) and Taraxacum fermented by Dongchimi (TDF). As for methodology, experiments were carried out to compare TD and TDF in components, protection effects for liver cells, anti-cancer effects on liver cells, and protection effects for brain cells in the aspects of liver function and immunity enhancement. Results : As shown in the chromatogram results, each valid component content increased in Taraxacum fermented by Dongchimi (TDF) for each time section. Of them, the valid component content at 36.80 minutes was approximately 2.7 times higher in TDF at 21.8% than in Taraxacum Dongchimi (TD) at 8.28%. TDF generated more excellent protection effects against the toxicity that caused oxidative damage to the liver cell(HepG2) with t-BHP than TD. The survival rate was low in TD of $100{\mu}g/m{\ell}$ and $300{\mu}g/m{\ell}$ and increased to 23.3% in TDF of $100{\mu}g/m{\ell}$. The survival rate was the highest at $300{\mu}M$ with a significant difference of 68.1%(P<0.05). Both TD and TDF showed effects of controlling nitric oxide production according to concentration with TDF recording a higher rate of controlling nitric oxide production than TD. There were significant differences(P<0.05) in the effects of controlling nitric oxide production at 200 ug/ml, 400 ug/ml in both groups. Especially the result TDF of $400{\mu}g/m{\ell}$ was thus similar to those of butein, the positive control group. Conclusion : The result of this studies is that Taraxacum fermented by Dongchimi (TDF) increased the valid component content compared with the simple mixture(TD). The findings clearly show that it is a material with the effects of improving immunity and liver cell protection. If fermentation methods are further developed to use it as a functional material, it will be subject to more opportunities of being used in other functional foods and make a contribution to integrated medicinal food development.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.34 no.11
• /
• pp.1859-1869
• /
• 2010

This study provides improved wrinkle recovery and UV protection capabilities as well as an antibacterial and deodorizing function to linen fabrics for summer shirts. The results obtained from this study are as follows. By setting catalyst concentration to 1.2% and DMDHEU concentration to 6% respectively and applying a heat treatment to them at $160^{\circ}C$ for 5 minutes, the decrease of fabric strength could be minimized and the crease resistance of linen fabrics improved. Compared to the treatment with DMDHEU only, the crease resistance of linen fabrics could be maintained and degradation of their properties could be more effectively prevented by applying the mixture of the UV absorber and the nano silver to the DMDHEU resin. The UV protection of fabrics could be improved by adding the UV absorber. Although the separate treatment of resin or the nano silver had no effect on the improvement of the UV protection properties for treated fabrics, they could increase the UV protection capability when they were combined with the UV absorber. Linen fabrics could possess an antibiosis and deodorizing capability by applying the mixture of the UV absorber, the nano silver, and the resin. The UV protection, crease resistance and flexibility of finished fabrics were maintained even after laundering. Washed treated fabrics maintained excellent antibiosis and odor free capabilities compared to untreated fabrics.

• Aerospace Engineering and Technology
• /
• v.3 no.2
• /
• pp.208-216
• /
• 2004

Advanced overload protection module for full scale airframe structural test was developed by improving the existing overload protection module. When performing the full scale airframe structural test, overload can be applied to the test article due to unexpected situations such as system shutdown, test article failure, and deficiency of design strength. Therefore, the overload protection module is needed for protecting the test article in unexpected overload situations. In this paper, the function of the existing overload protection module was summarized for each component and the problems encountered when using it in structural test were analyzed in addition, the development of advanced overload protection module was described.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.57 no.2
• /
• pp.91-95
• /
• 2008

The large AC generator fault may lead to large impacts or perturbations in power system. The generator protection control systems in Korea have been imported and operated through a turn-key from overseas entirely. Therefore a study of the generator protection field has in urgent need for a stable operation of the imported goods. In present, the algorithm using the current ratio differential relaying based DFT for stator winding protection or a fault detection had been applied that of internal fault protection of a generator. the DFT used for the analysis of transient state signal conventionally had defects losing a time information in the course of transforming a target signal to frequency domain. In this paper, the discrete wavelet transform (DWT) was applied a fault detection of the generator being superior to a transient state signal analysis and being easy to real time realization. The fault signals after executing a terminal fault modeling collect using a MATLAB package, and calculate the wavelet coefficients through the process of a muiti-level decomposition (MLD). The proposed algorithm for a fault detection using the Daubechies WT (wavelet transform) was executed with a C language and the commend line function for the real time realization after analyzing MATLAB's graphical interface. The advanced technique had improved faster a speed of fault discrimination than a conventional DFR based on DFT.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.4
• /
• pp.762-767
• /
• 2010

This paper describes characteristic of a light triggered thyristor investigated by experiment to adopt it into a main switch of a pulsed power unit. Triggering principle of the light triggered thyristor are referred with its structure and equivalent circuit. Operational principle and simulation result of a capacitive pulsed power circuit are explained. A variety of triggering conditions of triggering circuit and characteristics on turn-on, turn-off, voltage dividing in series operation, overvoltage protection function of the light triggered thyristor are investigated by experiments. Experimental result of 40 kJ pulsed power unit using the light triggered thyristor is presented.

• Journal of Chest Surgery
• /
• v.22 no.4
• /
• pp.580-588
• /
• 1989

The potential for enhancing myocardial protection by adding high-energy phosphate to cardioplegic solutions [St. Thomas Hospital solution] was investigated in a rat heart model of cardiopulmonary bypass and ischemic arrest. Creatine phosphate was evaluated as an additive to the St. Thomas Hospital cardioplegic solution. Creatine phosphate 10.0 mmol/L as the optimal concentration which improved recovery of aortic flow and cardiac output after a 30 minute period of normothermic [37oC] ischemic arrest. In comparing mechanical function in both groups the mean postischemic recoveries of aortic flow, cardiac output, stroke volume and stroke work [expressed as a percentage of its preischemic control] were significantly greater in STH-CP group than in CP- free control group. In addition to improving function and decreasing CK release, CP reduced reperfusion arrhythmias significantly decreasing the time between cross-clamp removal and return to regular rhythm from 81.8 * 13.9 [sec] in CP-free group to 35.9 * 6.8 [sec] in CP group [P< 0.05] so, exogenous CP exerts potent protective and antiarrhythmic effects when added to the St. Thomas Hospital cardioplegic solution. However, the mechanism of action remains to be elucidated.