• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.586-590
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• 2001

In this paper, a novel control scheme compensating source voltage unbalance and harmonic currents for hybrid active power filters is proposed, where no low/high-pass filters are used in compensation voltage composition. The phase angle and compensation voltages for source harmonic current and unbalanced voltage components are derived from the positive sequence component of the unbalanced voltage set, which is simply obtained by using digital all-pass filters. Since a balanced set of the source voltage obtained by scaling the positive sequence components is used as reference values for source current and load voltage, it is possible to eliminate the necessity of low/high-pass filters in the reference generation. Therefore the control algorithm is much simpler and gives more stable performance than the conventional method. In addition, the source harmonic current is eliminated by compensating for the harmonic voltage of the load side added to feedback control of the fundamental component.

• 대한수학회논문집
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• 제21권3호
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• pp.577-586
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• 2006

In this paper we will propose the methods for finding the non-invertible ideals corresponding to non-primitive quadratic forms and clarify the structures of class SEMIGROUPS of imaginary quadratic orders which were given by Zanardo and Zannier [8], and we will give a general algorithm for calculating power of ideals/classes via the Dirichlet composition of quadratic forms which is applicable to cryptography in the class semigroup of imaginary quadratic non-maximal order and revisit the cryptosystem of Kim and Moon [5] using a Zanardo and Zannier [8]'s quantity as their secret key, in order to analyze Jacobson [7]'s revised cryptosystem based on the class semigroup which is an alternative of Kim and Moon [5]'s.

• 음성과학
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• 제9권1호
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• pp.39-47
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• 2002

This paper proposes an effective method to remedy the acoustic modeling problem inherent in the usual log-normal Parallel Model Composition intended for achieving robust speech recognition. In particular, the Gaussian kernels under the prescribed log-normal PMC cannot sufficiently express the corrupted speech distributions. The proposed scheme corrects this deficiency by judiciously selecting the 'fairly' corrupted component and by re-estimating it as a mixture of two distributions using data-driven PMC. As a result, some components become merged while equal number of components split. The determination for splitting or merging is achieved by means of measuring the similarity of the corrupted speech model to those of the clean model and the noise model. The experimental results indicate that the suggested algorithm is effective in representing the corrupted speech distributions and attains consistent improvement over various SNR and noise cases.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1521-1521
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• 2001

The objective of the research being presented was to construct and calibrate a spectrometer for the analysis of single kernels of corn. In light of the difficulties associated with capturing the spatial variability in composition of corn kernels by single-beam spectrometry, a hyperspectral imaging spectrometer was constructed with the intention that it would be used to analyze single kernels of corn for the prediction of moisture and oil content. The spectrometer operated in the range of 750- 1090 nanometers. After evaluating four methods of standardizing the output from the spectrometer, calibrations were made to predict whole-kernel moisture and oil content from the hyperspectral image data. A genetic algorithm was employed to reduce the number of wavelengths imaged and to optimize the calibrations. The final standard errors of prediction during cross-validation (SEPCV) were 1.22% and 1.25% for moisture and oil content, respectively. It was determined, by analysis of variance, that the accuracy and precision of single-kernel corn analysis by hyperspectral imaging is superior to the single kernel reference chemistry method (as tested).

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.274-275
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• 2011

Fault current problems is considered a serious issue in the power system because large fault currents not only cause many side effects to the equipments of power system but also lead to severe problems, such as blackouts. This paper deals with the structural analysis and 3-phase fault current stability of the future Seoul metropolitan power system. The simulation composition and analysis are performed with the 4th KEPCO power supply planning data using PSS/e. Through the results of the simulations, it can be observed that the future Seoul metropolitan system results in a fault current which exceeds the circuit breaker (CB) rate. This unremovable fault current can cause critical damage to power system. To resolve the problem, the algorithm for the application of Voltage Sourced Converter Back-to-Back High Voltage Direct Current (VSC BTB HVDC) is being proposed. where the most suitable location for solving fault current problem in Seoul metropolitan area is being implemented.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2001년도 춘계 학술대회논문집
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• pp.45-50
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• 2001

An approach of composing a performance optimized computational code is suggested for latest microprocessors. The approach named as localization is a concept of minimizing the access to system's main memory and maximizing the utilization of second level cache that is common to all the latest computer system. The localized compositions of LU-SGS scheme for fluid dynamics were made in three different levels and tested on three different microprocessor architectures most widely used in these days. The test results of localization concept showed a remarkable performance, that is the showing gain up to 4.5 times faster solution than the baseline algorithm $450\%$ for producing an exactly the same solution.

• 한국컴퓨터산업학회논문지
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• 제2권10호
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• pp.1261-1268
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• 2001

함수언어는 여러 가지 유용한 특징에도 불구하고 상태를 나타내기 위한 효율적인 방법을 제공하지 못하고있다. 함수언어의 표현력을 높이기 위해서는 함수언어의 의미를 위배함이 없이 상태를 명시적으로 나타내기 위한 방법이 요구된다. 이 연구에서는 순수 함수언어의 성질을 위배함이 없이 상태를 표현하기 위한 명령형 함수언어 $\lambda$st-계산을 설계하였고 제안된 명령형 함수언어를 감축하기 위한 알고리즘을 구성하였다. $\lambda$-계산에 명시적인 상태 구성자를 확장한 $\lambda$st-계산 모델은 상태의 합성 개념을 도입하고 감축규칙을 간략화 함으로써 구문구조의 표현력을 향상시켰다.

• 대한전자공학회논문지
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• 제26권11호
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• pp.1839-1849
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• 1989

An optimal variable assignment algorithm is presented as a decomposition method of MVL functions. A given 3-valued combinational logic function is disintegrated into subfunction composed of the function dependant relation, then extracted implicant output elements from subfunctions are assigned to a T-gates. As a circuit implementation tool, a programmable integarated T-gate module is proposed, and the construction procedure of combinational MVL functions is systematized in each step. This method is expected to give properties of the systematic procedure, possibility of T-gate number reduction, unification of module, and flexibility of module composition. Specially variable decomposition method can be pointed out as an approach to solving the limitation problem of the input and output terminal number in VLSI implementations.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1997년도 추계학술대회 학술발표 논문집
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• pp.315-320
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• 1997

Rule minimization technique adapted from rough set theory was applied to remove redundant knowledge which is not necessary to make a knowledge base. New algorithm to diagnose fault using Improved Fuzzy Cognitive Maps(I-FCMs), and Fuzzy Associative Memory(FAM) is proposed. I-FCM[22] is superior to gathering knowledge from many experts and descries dynamic behaviors of systems very well. I-FCM is not only a knowledge base, but also a inference engine. FAM has learning capability like neural network[12]. Rule minimization and composition of I-FCM and FAM make it possible to construct compact knowledge base and breaks the border between inference engine and knowledge base.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1124-1129
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• 2003

In mechanical design, design process is mainly composed of design, explanation and evaluation. In this paper, Using Genetic Algorithms (GA), Evolutionary computation is introduced as new design process. This method promote the efficiency and power of design. Due to the known characteristics of the stage, the approach basically involves a synthetic design method with the composition of building blocks representing the elements of mechanical objects. In order for the building blocks to be more suitable for representation and evolution of mechanical structures, Elementary Cell Blocks (ECBs) are introduced as new building blocks. In this paper, we have demonstrated the implementation of the approach with the design of gear systems.