• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.39-44
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• 2006

Pattern noise in the Delta-Sigma modulator is a well Known phenomenon that intrigued many circuit designers. These noise appear as the modulator output falls into a cyclic mode of operation. This paper addresses the dependence of these tone signal upon the system topologies. Among the four well known single-stage DSM topologies, namely Cascade of Integrators with Feedback Form(CIFB), Cascade of Integrators with Feedforward Form(CIFF), Cascade of Resonators with Feedback Form(CRFB), and Cascade of Resonators with Feedforward Form(CRFF), resonator type DSMs turn out to be more susceptible to the pattern noise than the integrator type. Noise transfer functions of the investigated topologies are also presented.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.67-73
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• 2006

In this paper, a reconfigurable model following flight control method is proposed based on direct adaptive scheme using parameter estimation. Adaptive control scheme updates the control gains to make the system output follow the reference output even when fault occurs. By adopting the frequency domain parameter estimation method, system changes by the fault can be estimated. Recursive Fourier transformation is used for system identification. Using recursive Fourier transform, the proposed adaptive control algorithm guarantees the system stability and improves the system characteristics. To evaluate the performance of proposed control method, numerical simulations are performed.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.4
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• pp.272-278
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• 2007

In this paper, we present an automated API translator for embedded software development based on a model-driven approach. Since MDA(Model Driven Architecture) provides little support for the development of embedded software, we propose a new method which contains the MDA's advantage, automation of implement process, and can solve the problem of real-time overhead. First, we define 'generic APIs' which do not depend on any RTOS's but provide most of typical RTOS services. We can describe RTOS-related behaviors of target application using these generic APIs in a CIC(Common Intermediate Code). Then, we propose a transformation tool for translating a CIC using generic APIs into a C-code for specific RTOS. The proposed API translator converts them into C-code using XML transformation rule which is defined outside. It indicates that an API translator extends to other RTOS's by modifying or adding the transformation rule. From the experiment, we validate the proposed method.

• Journal of the Korea Society of Computer and Information
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• v.13 no.5
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• pp.53-67
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• 2008

At present, for reuse of similar domains between feature model and class model. researches of transformation at the model level and of transformation using ontology between two models are being made. but consistent transformation through metamodel is not made. And the factors of modeling transformation targets are not sufficient, and especially, automatic transformation algorithm and supporting tools are not provided so reuse of domains between models is not activated. This paper proposes a method of transformation from feature model to class model using ontology on the metamodel. For this, it re-establishes the metamodel of feature model, class model, and ontology, and it defines the properties of modelling factors for each metamodel. Based on the properties, it defines the profiles of transformation rules between feature mndel and ontology, and between ontology and class model, using set theory and propositional calculus. For automation of the transformation, it creates transformation algorithm and supporting tools. Using the proposed transformation rules and tools, real application is made through Electronic Approval System. Through this, it is possible to transform from the existing constructed feature model to the class model and to use it again for a different development method. Especially, it is Possible to remove ambiguity of semantic transformation using ontology, and automation of transformation maintains consistence between models.

• The KIPS Transactions:PartD
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• v.13D no.2 s.105
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• pp.235-240
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• 2006

Software architectures may be described using text-based architecture description language(ADL). The key goals of an ADL are to communicate alternate designs between different stakeholders, to detect reusable structures, and to record design decisions. This paper provided a solution to the representation problem by creating a tool for three-dimensional representation of architectural viewpoints. The tool consisted of an architecture description language(VTADL) to first describe the software architectures and viewpoints on the architectures; and a VTADL-to-VRML translator to translate each viewpoint into a separate virtual reality world The goal of the paper was to devise algorithms for translating an ADL into effective VRML representations based on the desired viewpoint. The VRML representations were intended to enhance comprehension on the overall design and to improve communications between diverse stakeholders.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.194-195
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• 2011

본 논문은 Bi-directional Inverter(BDI)에 DQ 변환을 적용한 소신호 등가 모델과 이중 루프 제어기 설계에 대해 제안한다. 일반적으로 외부루프의 경우 동적 특성이 매우 느리기 때문에 외부루프 전달함수를 고려하지 않고 설계하는 경우가 많다. 결과적으로 시스템의 안정성이나 동적 특성이 설계한 것과 다르게 나타날 수 있다. 따라서 원하는 특성을 만족하기 위해 실험적 시행착오를 거쳐 설계를 하게 된다. 본 논문에서는 정확한 소신호 등가 모델을 제시하고 제어기를 설계한다. 제안된 방식은 PSIM 시뮬레이션 및 실험을 통해 회로해석과 소신호 등가모델의 타당성 및 제어기 설계의 타당성을 증명하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.731-736
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• 1994

STEP(Standard for the Exchange of Product Data)은 제품데이타의 표현 및 교환에 관한 국제표준으로서, 특정 시스템에 관계없이 제품생산에 관계된 정보를 표현할 수 있는 중립표준을 제공하는데 그 목적이 있다. STEP은 화일교환을 위한 중립표준을 제공할 뿐만 아니라 , 제품데이타베이스를 수현하는 기반을 제공한다. 따라서, 향후 STEP은 좁은 의미 로서는 시스템간의 데이타 교환의 표준으로,넓은 의미로서는 컴퓨터통합 생사시스템(CIMS) 의 구현시 정보모델의 근간으로 사용될 것으로 예상된다. 본 연구에서는 STEP을 이용하여 CAD의 형상정보와 특징형상정보를 변환하는 변환기를 개발하였다. 변환기의 개발은 크게 3단계로 나뉘어 지는데, 1) STEP에서 제정한 데이타 정의어인 EXPRESS를 이용하여 각 CAD 시스템에서 사용하는 포멧을 따라 형상정보및 특징형상정보의 스키마를 모델링하는 단계 2) 실제데이터를 이용하여 모델링된 스키마에 맴핑(mapping0하는 단계, 3) 피니컬 화일로 변환하는 단계를 거치게 된다. 이글에서는 STEP을 이용한 특징형상정보의 호환을 위한 변환기의 구조를 제안하고, EXPRESS를 이용한 스키마 모델링 및 특징형상 정보의 변환사례를 소개한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.8
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• pp.801-808
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• 2004

In this paper, we proposed the grating parallel plate waveguide structure for converting a linearly polarized wave to a circularly polarized wave. For the design of the polarizer, the moment method and Floquet's theorem are applied under two assumptions that the incident wave is a plane wave and the structure is infinitely periodic. In order for the more precise design, we performed the near-field analysis for the finite polarizer structure using MATLAB. By comparing with the measured results obtained by the near-field arrangement, we verified the correctness of our near-field analysis. By taking the ideal assumptions considered in the initial design procedure into account, newly designed modified dimensions for the polarizer was suggested which give improved performance.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.253-260
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• 2007

A multimedia converter is used to create media suitable for own environment. If the data complying with own demands can not be created, it may accompany with a problem that has to convert the data with another transcoder. In addition, conventional converters do not consider source QoS and target QoS sufficiently, meaning that users should have a significant knowledge base about various media in order to obtain desired results. These problems become limits on the UMA(Universal Multimedia Access) environment. In this paper, we create a suitable transcoding path before performing the Digital Item conversion in consideration of source QoS and target QoS. The created transcoding path performs the adaptive transcoding using unit exchanges featuring connectivity. The consideration of QoS allows users to use the multimedia easily. Since the proposed model, in addition, use the unit transcoder, it provides a excellent adaptive capability for new QoS.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.3
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• pp.231-239
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• 1998

This paper presents the dynamic analysis and control loop design of a zero voltage switching full bridge (ZVS-FB) PWM DC/DC converter. The small-signal model is derived incorporating the effects of phase shift control and the utilization of transformer leakage inductance and power FET junction capacitance to achieve zero voltage resonant switching. These effects are modeled by introducing additional feedforward and feedback terms for duty cycle modulation. Based on the results of the small-signal analysis, the control loop is designed using a simple two-pole one-zero compensation circuit. To show the validity of the design procedures, the small signal analysis of the closed loop system is carried out and the potential of the zero voltage switching and the superiority of the dynamic characteristics are verified through the experiment with a 2 kW prototype converter.