• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.4
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• pp.23-30
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• 1980

All the resistors in the active RC filter networks cab be replaced by the switched capaciters, The swiftched capacitor is much bet tar than a resistor in temperature and linearity characteristics, and the former can be fabricated on the much smaller silicon area than the latter. In this paper, it is given the generaliged design method of the active SC filter from the active RC filter using Bilinear Z-transformatirm. SC filtering techniques using Bilinear Z-transform enable us to realize the FDNR and Gyrator filters which could not be realized by the exsisting designs 1 and to utilize the processing of signals at much higher frequencies than the conventional design method. Experiments show that the response of the active SC filter is similiar to that of its prototype active RC filler.

• Journal of KSNVE
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• v.7 no.1
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• pp.135-142
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• 1997

This paper presents a digital modeling technique of the distributed system. The basic idea of the proposed technique is to discretize a continuous system with respect to the spatial coordinates using bilinear method. The response of the discretized system is analyzed by Laplace transform and z-transform. The computational results in torsional shaft and Timoshenko beam using the proposed technique are compared with the exact solutions and the results of finite element method.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.04b
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• pp.849-852
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• 2002

전통적으로 소프트웨어 공학분야에서는 소프트웨어 설계 및 개발을 위한 자동화도구와 정형화기법이 적용되었으며, 안전한 보안시스템의 개발을 위해서도 수학적인 명세와 검증도구를 사용하는 경우, 보다 안전하고 완전한 보안시스템을 구축할 수 있다. 본 연구는 정형화 명세언어인 Z를 이용하여 보안시스템을 기술하고, 기술된 명세를 소프트웨어 검증도구를 이용하여 보안시스템이 제공하는 보안특성 만족 여부 점검을 목적으로 한다. 이를 위해 본 논문에서는 수학적으로 기술된 시스템에 대한 명세를 Z스키마로 변환하는 변환규칙을 기술하고, 이와 함께 Z언어 검증도구인 Z/EVES를 이용한 검증결과를 제시한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.449-459
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• 2014

The proposed 2+1 view integrated metamodel defined formerly with a graphical class model can not be guaranteed the syntactic clarity and accuracy precisely for the metamodel due to the informal specification. This paper specifies the syntactic semantics formally for the 2+1 view integrated metamodel using Z and Object-Z and checks the accuracy of the metamodel with Z/Eves tool. The formal specification is expressed in Z and Object-Z schema separately for syntax and statics semantics of the 2+1 view integrated metamodel, which applying the converting rule between class model and Z/Object-Z. The accuracy of the Z specification for the metamodel is verified using Z/Eves tool, which can check the syntax, type, and domain of the Z specification. The transformation specification and checking of the 2+1 view integrated metamodel can help establish more accurate the syntactic semantics of its construct and check the accuracy of the metamodel.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.2
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• pp.51-59
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• 2010

Two logic transformations, De Morgan and re-substitution, are sufficient to convert a unate gate network (UGN) to a more general balanced inversion parity (BIP) network. Circuit classes of interest are discussed in detail. We prove that De Morgan and re-substitution transformations are test-set preserving for path delay faults. Using the results of this paper, we can easily show that a high-level test set for a function z that detects all path delay faults in any UGN realizing z also detects all path delay faults in any BIP realization of z.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.227-232
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• 1995

This paper presents a digital modeling technique for the distributed parameter system. The basic idea of the proposed technique is to discretize a continuous system with respect to the spatial coordinate using the approximate methods such as bilinear method and backward difference method. The response of the discretized system is analyzed by Laplace transform and Z transform. The computational result of the proposed technique in a torsional shaft is compared with the exact solution and the result of the finite element method.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.169-172
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• 2007

This paper presents circuit models and control algorithms of distributed generation system(DGS) which consists of Z-type converter and PWM inverter. Z-type converter which employs both the L and C passive components and shoot-through zero vectors instead qf the conventional DC/DC converter in order to step up DC-link voltage. Discrete time sliding mode control with the asymptotic observer is used for current control. This system am be used for power conversion of DC renewable energy.

• Proceedings of the Korea Information Processing Society Conference
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• 2001.04b
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• pp.1009-1012
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• 2001

일반적으로 크고 복잡한 소프트웨어 시스템은 커다란 다이아그램의 집합으로 구성되지만 이들 각각의 다이아그램들이 일관성이 있고 완전한가를 알기는 매우 어렵다. 이러한 문제를 해결하기 위하여 [1]에서는 최근 객체지향 개발에서 많이 사용되고 있는 UML 다이아그램들에 대한 일관성과 완전성을 검사하기 위하여 각 다이아그램들을 ER 모델로 표현하고, 각 다이아그램에 대한 공통된 표현으로 통합된 ER 다이아그램을 제공하였다. 이렇게 통합된 다이아그램은 일편의 집합과 함수들을 사용하여 정형적으로 명세되며, 이러한 정형 명세를 기반으로하여 일관성과 완전성 검사를 수행하기 위한 규칙을 제공하였다. 그러나 [1]에서 정형적으로 명세된 집합과 함수를 실제로 사용하기 위해서는 우리가 알고있는 정형 명세 언어로 변환할 필요성이 있다. 따라서 본 논문에서는 이러한 집합을 추상자료형으로 명세하여 정의하고, 추상자료형으로 표현된 명세를 우리가 잘 알고 있는 Z 명세로 변환하여 검증 도구를 설계하는 기초로 사용하고자 한다. Z 명세는 쉽게 실행가능한 형태로 변환되어 검증 시스템을 구축할 수 있게 된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.143-149
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• 1996

Forecasts of the monthly catches of anchovy in Korea were carried out by the seasonal Autoregressive Integrated Moving Average (ARIMA) model and spectral analysis. The seasonal ARIMA model is as follows: $$(1-0.431B)(1-B^{12})Z_t=(1-0.882B^{12})e_t$$ where: $Z_t=value$ at month $t;\;B^{p}$ is a backward shift operator, that is, $B^pZ_t=Z_{t-p};$ and $e_t=error$ term at month t, which is to forecast 24 months ahead the anchovy catches in Korea. The prediction error by the Box-Cox transformation on monthly anchovy catches in Korea was less than that by the logarithmic transformation. The equation of the Box-Cox transformation was $Y'=(Y^{0.58}-1)/0.58$. Forecasts of the monthly anchovy catches for $1991\~1992$, which were compared with the actual catches, had an absolute percentage error (APE) range of $1.0\~63.2\%$. Total observed annual catches in 1991 and 1992 were 170,293 M/T and 168,234 M/T respectively, while the predicted catches were 148,201 M/T and 148,834 M/T $(API\;13.0\%\;and\;11.5\%,\;respectively)$. The spectrum analysis of the monthly catches of anchovy showed some dominant fluctuations in the periods of 2.2, 6.1, 10.2 12.0 and 14.7 months. The spectrum analysis was also useful for selecting the ARIMA model.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.69-80
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• 2012

In this paper, we studied the time-domain measurement and analysis techniques using a network analyzer for characterization UWB antenna link radiating impulse signal. For this purpose, we developed the CZT(Chirp z-Transform) algorithm which has characterized zoom-in function and transformed the acquired data from network analyzer to time domain format. Using the CZT algorithm, we proves that it would be better efficient and more faster than the DFT for analyzing the waveform and also be able to zoom-in the arbitrary region.