• 대한전자공학회논문지
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• 제24권4호
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• pp.658-666
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• 1987

In this paper, a new mehtod of reducing harmonics that involved in input AC line currents or in output DC voltage of the converter system is presented. which is due mainly to the quipment of 2-3 switching taps on interphase reactor. In case that the 3 tap method is applicable to conventional 12 pulse converter, it could not bring to an effect of reducing harmonics under firing angle 15\ulcorner To solve these problems, 24 pulse or 36 pulse converter is controlled by microprocessor. The former is performed in 2 tap method when \ulcorneris less than 15\ulcorner the latter in 3 tap method when it is more then 15\ulcorner Therefore the originality of this paper liea in microprocessor based equipment of the 2-3 switching taps on interphase reactor. I applied this method to the 12 pulse converter, and proved validity of that theoretically and experimentally.

• 한국조명전기설비학회지:조명전기설비
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• 제8권2호
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• pp.69-76
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• 1994

An effective method for reducing the harmonics in double connected modified current source inverter[MCSI] by switching taps on auto transformer is presented in this paper. The proposed system operates as like a 24 step MCSI by adding only tap changing auxiliary circuit which consists of several taps and static switching elements to the 12 step multiple inverter, which is double connected three-phase six-step MCSI with an auto transformer. The basic theories of the proposed inverter systems for analyzing the output waveforms are described. And to optimize the effectiveness of the harmonic reduction, the optimum turn ratio and the tap changing control angle of auto transformer are decided by digital simulation and its validity is verified by experiment. Although the construction of the proposed inverter is very simple, it is clarified that the output waveform of the inverter is almost the same as that of the conventional 24 step multiple inverter under the optimum condition.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2015년도 추계학술대회
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• pp.102-106
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• 2015

항공 운송량의 증가로 운항 중 예상치 못한 난류(Turbulence)에 직면하는 경우도 증가하고 있다. 이로 인한, 손님/승무원의 부상, 화물 손상, 항공기 효율성 하락 등으로 많은 Cost가 발생하고 있으며, 항공 안전에도 치명적인 위협이 되고 있다. 하지만, 이에 대한 정보는 운항 중인 항공기의 조종사기상보고(Pilot Weather Reports, PIREP)에 의존하여 발생 지역을 예측하고 있으나, 보고시간 지체에 따른 부정확한 위치, 주관적인 강도 예측으로 실제 유사 지역을 운항하는 항공기에 도움을 주는데 한계가 있다. 금번 논문에서 TAPS(Turbulence Auto PIREP System)의 원리와 실제 운영하는 항공사의 활용 방안을 고찰하여, 정보의 자동 송/수신을 통한 실시간 난류 정보 제공으로 위험 요인을 사전 인지하여 제거할 수 있는 방안을 살펴보고자 한다.

• 전자공학회논문지A
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• 제33A권4호
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• pp.18-26
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• 1996

In this paper we propose a new dual structured tap selection algorithm for voice echo canceller in digital cellular communication system, investigating adaptive filtering algorithms for echo cancellation in long distance telephony or mobile communication system. The proposed algorithm has a two-stage processing structure that after a dispersive region in an impulse response of an echo path is found out, the tap coefficients of a short length filter are adjusted adaptively for the region, because the impuse response has a very little portion of the dispersion. Simulation results show that the proposed algorithm with 256 taps gives a performance of convergence speed superior to both full-tap normalized least mean with 256 taps gives a performance of convergence speed superior to both full-tap normalized least mean square (NLMS) and a scrub taps waiting in a queue (STWQ) algorithms by about eighty per cent, also to a tap selection algorithm by about twenty per cent. And the resutls diplay that if the more tap coefficients are used due to a long delayed dispersive zone, the proposed algorithm produces the better performance.

• 전자공학회논문지C
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• 제34C권6호
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• pp.22-27
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• 1997

This paper propose a novel VLSI architecture for a multiplierless FIR filter chip providing variable-length taps. To change the number of taps, we propose two special features called a data-reuse structure and a recurrent-coefficient scheme. These features consist of several MUXs and registers and reduce the number of gates over 20% compared with existing chips using an address generation unit and a modulo unit. Since multipliers occupy large VLSI area, a multiplierless filter chip meeting real-time requirement can save large area. We propose a modified bit-serial multiplication algorithm to compute two partial products in parallel, and thus, the proposed filter is twice faster and has smaller hardware than previous multiplierless filters. We developed VHDL models and performed logic synthesis using the 0.8.mu.m SOG (sea-of-gate) cell library. The chip has only 9,507 gates, was fabricated, and is running at 77MHz.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2196-2199
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• 2003

With the development of digital signal processor(DSP), digital pulse compressor (DPC) is commonly used in radar systems. A DPC is implemented by using finite impulse response(FIR) filter algorithm in time domain or fast Fourier transform(FFT) algorithm in frequency domain. This paper compares the computation complexity tot these two methods and calculates boundary Fm filter taps that determine which of the two methods is better based on computation amount. Also, it shows that the boundary FIR filter taps for DSP, ADSP21060, and those for computation complexity have similar characteristic.

• Journal of Computational Design and Engineering
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• 제3권4호
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• pp.337-348
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• 2016

An experimental approach is presented for the measurement of wear that is common in the threading of cold-forged steel. In this work, the first objective is to measure wear on various types of roll taps manufactured to tapping holes in microalloyed HR45 steel. Different geometries and levels of wear are tested and measured. Taking their geometry as the critical factor, the types of forming tap with the least wear and the best performance are identified. Abrasive wear was observed on the forming lobes. A higher number of lobes in the chamber zone and around the nominal diameter meant a more uniform load distribution and a more gradual forming process. A second objective is to identify the most accurate data-mining technique for the prediction of form-tap wear. Different data-mining techniques are tested to select the most accurate one: from standard versions such as Multilayer Perceptrons, Support Vector Machines and Regression Trees to the most recent ones such as Rotation Forest ensembles and Iterated Bagging ensembles. The best results were obtained with ensembles of Rotation Forest with unpruned Regression Trees as base regressors that reduced the RMS error of the best-tested baseline technique for the lower length output by 33%, and Additive Regression with unpruned M5P as base regressors that reduced the RMS errors of the linear fit for the upper and total lengths by 25% and 39%, respectively. However, the lower length was statistically more difficult to model in Additive Regression than in Rotation Forest. Rotation Forest with unpruned Regression Trees as base regressors therefore appeared to be the most suitable regressor for the modeling of this industrial problem.

• Asian Pacific Journal of Cancer Prevention
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• 제16권15호
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• pp.6299-6302
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• 2015

Background: The rise in consumption of tobacco products among youth is a public health concern in India. Several studies have shown that advertisements promoting tobacco products influence decisions and behaviour of youth towards smoking. Objective: To ascertain which method of Tobacco Advertising, Promotion and Sponsorship (TAPS) was more influential for initiating tobacco use in youth in India. Materials and Methods: The secondary data of youth (15-24 years) from nationally representative Global Adult Tobacco Survey (GATS) conducted in 2009-2010 was analyzed. Odds ratio and p-value were used to know the association between TAPS and initiation of use of tobacco products among youth. Logistic regression was used to determine the most significant means of TAPS altering the youth's behaviour towards tobacco products. Results: Out of 13,383 youths, 1,982 (14.7%) used smokeless forms of tobacco and 860 (6.38%) used smoke forms. Logistic regression reveals that promotional activities mainly through cinemas (p<0.05) and providing free samples of tobacco products (p < = .001) were most influential means of initiating consumption of tobacco products among youth. Conclusions: The smoking in youth is associated with watching advertisements particularly in cinema and promotional activities like distribution of free samples, coupons and sales on the price of tobacco products. Stronger legislative measures should be enforced to curb promotional advertisements in cinemas and distribution of free samples.

• Journal of Power Electronics
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• 제17권2호
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• pp.522-532
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• 2017

This paper presents a novel integrated structure for a cascaded distribution static compensator (D-STATCOM) and distribution transformer for medium-voltage reactive power compensation. The cascaded multilevel converter is connected to a system via a group of special designed taps on the primary windings of the Dyn11 connection distribution transformer. The three-phase winding taps are symmetrically arranged and the connection point voltage can be decreased to half of the line-to-line voltage at most. Thus, the voltage stress for the D-STATCOM is reduced and a compromise between the voltage rating and the current rating can be achieved. The spare capacity of the distribution transformer can also be fully used. The working mechanism is explained in detail and a modified control strategy is proposed for reactive power compensation. Finally, both simulation and scaled-down prototype experimental results are provided to verify the feasibility and effectiveness of the proposed connection structure and control strategy.

• 환경위생공학
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• 제9권2호
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• pp.50-57
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• 1994

Densities of total and injured coliforms in treated water( TW ) and three tap water salt pies( Taps Kl, K2 and K3) of Ku- eui water treatment plant and one tap water sample( Tap T) of Tuk- do water treatment plant were measured 23 times from 1991 to 1992. Coliform regrowth in the water distribution system occurred three times during the study period. When the regrowth episode occurred, injured coliforms were always but total coliforms were not always detected in treated water. Mean densities of total coliforms in TW, and Taps Kl, K2, K3 and T were 0.8, 2.3, 1.9, 1.4 and 2.1 cfu/100mℓ by membrane filtration method using m- TF agar and those of injured coliforms were 3.4, 2.8, 2.5, 2.7 and 2.9 c1u/100mℓ using mondo- LES agar. The injury rates of TW and Taps Kl, K2, K3 and T were 89.5,77.4,67.9, 82.8 and 75.9%, respectively. The high injury rate of coliform bacteria in Seoul water supply can cause regrowth problems in distribution systems due to the repair of injured cells under an appropriate condition. It is recommended the injured coliforms should be measured in drinking water since they can lead to a significant underestimation of total coliforms and result in an inaccurate evaluation of the potential health risks.