• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.7
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• pp.668-679
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• 1990

The fully digitalized inveter has some difficulties in implementation because of the limitation of available memory capacity and computation time. This paper describes a new PWM(Pulse Width Modulation) Inverter technique which linearizes switching angle characteristics of SHEPWM(Selected Harmonic Eliminatin Pulse Width Modulation) Inverter. Also the detailed description of the scheme along with the realization is presented. The simulation and experimental results show that the proposed schemes have the advantates such as good voltage waveforms and memory-saving.

• Environmental and Resource Economics Review
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• v.15 no.2
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• pp.355-386
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• 2006

This paper analyses recent regional development policies being carried out in Japan and the U.S. Such policies are formed on the sustainability principle aiming at the realization of circula-flow economy and zero waste society. The study here illuminates Japan's Eco-town project and three cases of eco-industrial developments in Minnesota. Such projects have gone from improving industry competitiveness through constructing clean production systems on the company level to improving national competitiveness through constructing a 'circular society' on the government level. Japan included the realization of a 'circular society' as its government's top agenda because it recognized that environmental pollution stems from the inefficient use of natural resources. Eco-town project is a regional development policy specifically reflecting such recognition. The eco-efficiency based city development approaches in Minnesota are but small examples of the new wave in regional development in the developed countries. We need to go beyond emphasizing eco-friendly and ethical management to just the companies. The government itself needs to design national policies based on environmental sustainability.

• The Journal of the Acoustical Society of Korea
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• v.8 no.4
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• pp.53-59
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• 1989

A new proposed method can separate heart sounds and lung sounds by the realization of adaptive noise canceler using adaptive lattice Wiener filter in contrast to adaptive transversal LMS filter and high pass filter as before. Lung sounds and ECG signal are detected for this purpose, and especially the second heart sounds are reduced by finding T wave location with a T wave seeking algorithm. As a result, for heart sounds reduction It was found that adaptive transversal LMS filter required 100-200's orders, 75-100's orders In adaptive transversal MLMS filter, and only 10-20's orders in adaptive lattice Wiener filter. Adaptive filtering technique has shown greater accuracy than high pass filtering without loss of low frequency component.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.9
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• pp.872-875
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• 2016

In this paper, the turnstile junction-based Ortho-Mode Transducer(OMT) is designed and manufactured. It is usually well-known that turnstile junctions have symmetry structure of waveguide so the higher order modes, which occurs inside the waveguide, can be cancelled. Because of these symmetrical properties, the turnstile junction-based OMTs have merits like high transmission and low return loss characteristic in broadband and two different modes propagate orthogonally in common port resulting in the fully realization of double polarization. The designed OMT has the application of Radar Seeker and operates in W-band(94 GHz), the millimeter wave frequency. The average of return loss value of manufactured OMT is lower than -20 dB and it has bandwidth characteristic of over 500 MHz.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4B
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• pp.371-377
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• 2011

Users of the Information Age, IT usage patterns of the wired broadband information services and various forms of the same quality wireless multimedia services are required. Changes of these times the next-generation mobile communications (IMT-Advanced) has emerged as the necessity of developing its current voice and packet data communications on the move in the high-speed 100Mbps, 1Gbps in stationary and slow data transmission rates up to fixed-mobile convergence based on needed to provide ubiquitous service platform for the realization of IMT-Advanced is the time for preparation. In particular, 3-5GHz band, focused on mobile communications can be used to secure the necessary frequency band relocated and the existing crosstalk analysis methodology developed for the services rendered, and the frequency of such results to obtain new spectrum for IMT-Advanced for the country to secure the frequency characteristics and IMT-Advanced 3-5GHz band for the radio frequency of the characterization techniques necessary to develop a national wireless communication interference and frequency-based technology acquisition and management skills were identified.

• Iberoamérica
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• v.22 no.1
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• pp.1-30
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• 2020

Recently, in the conservative wave in Latin America, the political participation of the conservative Pentecostal Church has been highlighted. This article analyzes the impact of this political participation on democracy and its development, based on the case of Brazil. First, the Pentecostal churches contributed greatly to religious pluralism, but show an exclusive and aggressive attitude toward other religions and ideologies. Also, in the process of selecting official candidates, most members of the churches are politically mobilized according to the unilateral decisions of the leadership, and these elected candidates serve the specific corporatist interests of their own denomination or church rather than the public interest. In addition, the purpose of political participation to obtain public offices is also a stumbling block to the development of democracy in Brazil by placing it in the direct realization of a specific religious interests or values of the rebuilding of the Christian kingdom.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1822-1828
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• 2008

This paper presents design parameter calculation methodology and its realization to construction for the 10/350${\mu}s$ lightning impulse current generator(ICG) modelled as double exponential function waveform with characteristic parameters ${\alpha},{\beta}$. Matlab internal function, "fzero" was applied to find ${\lambda}={\alpha}/{\beta}$ which is solution of nonlinear equation linearly related with two wave parameter $T_1$ and $T_2$. The calculation results for 10/350${\mu}s$ lightning impulse current show very good accuracy with error less 0.03%. Two type of 10/350${\mu}s$ ICGs based on the calculated design circuit parameters were fabricated by considering the load variation. One is applicable to the MOV based Surge protective device(SPD) for less 15 kA and the other is to test small resistive devices such as spark gap arrester and bonding device with maximum current capability 30 kA. The tested waveforms show error within 10% in comparison with the designed estimation and the waveform tolerance recommended in the IEC 61643-1 and IEC 60060-1.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.834-840
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• 2007

A generator plays an important role in transferring an electric power to power system networks. The generator protection systems in Korea have been imported and operated through a tum-key from overseas entirely. Therefore, a study of the generator protection field has in urgent need for a stable operation of the imported goods, and for preparation of next generation protection system. The paper describes the fault detection algorithm using WT(Wave!et Transform) of currents for a generator protection. The fault current signals after executing a terminal fault modeling collect using a MA TLAB package, and calculate the wavelet coefficients through the process of a multi -level decomposition (MLD). The proposed algorithm for a fault detection using the Daubechies WT (wavelet transform) was executed with a C language for the command line function and for the real time realization after analyzing MATLAB's graphical interface. The advanced technique had complemented the defects of a DFT by applying a Daubechies WT. and had improved faster a speed and more accurate of fault discriminant than a conventional DFR.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.233-233
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• 2008

A piezoelectric ultrasonic linear motor shaped with 'Butterfly' wings has been developed for thin electronics such as cellular phone and PDA. The butterfly piezoelectric transducer is simply composed of an elastic plate, which includes a tip for energy transfer and two protrusions to fix it, and two piezoelectric ceramics. Contact materials, such as a brass, and steel and alumina can make it possible to improve dynamic properties of the motors over a wide range of tribological conditions. The dynamic properties of the motor have been intensively measured and analyzed according to the applied voltage wave forms at the various frequencies. The results of numerical study and experimental investigation will be used for the future optimization of the actuator and the realization of the advanced ultrasonic motor.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.9
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• pp.903-909
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• 2007

A fatigue capsule is one of the special capsules to investigate the fatigue characteristics of the nuclear materials during an irradiation test in a research reactor, HANARO. In this study, the performance test and the preliminary fatigue test results by using a cyclic load device newly developed for a fatigue capsule are described. In order to obtain the characteristics such as a realization and a controllability of the periodic wave shape and the relationship between the pressure and the load, a spring and rigid bar specimens are used. The fatigue test for the 316L stainless steel specimen with 1.8mm in diameter and 12.5mm in gage length is also performed under the same conditions as the temperature($550^{\circ}C$) of the specimen during irradiation tests. As a result of the test, the fracture of the specimen occurs at a total of 70,120 cycles(about 12 days), and the displacement in this case is 2.02 mm. It is expected that these results will be used for determining test conditions and a comparison of the in-pile fatigue test results.