• Journal of KIISE:Software and Applications
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• v.29 no.10
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• pp.703-725
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• 2002

It is well recognized that component-based development (CBD) is an effective approach to manage the complexity of modem software development. To achieve the benefits of low-cost development and higher productivity, effective techniques to maximize component reusability should be developed. Component is a set of related concepts and objects, and provides a particular coarse-grained business service. Often, these components include various message flows among the objects in the component, called 'business workflow`. Blackbox components that include but hide business workflow provide higher reusability and productivity. A key difficulty of using blackbox components with business workflow is to let the workflow be customized by each enterprise. In this paper, we provide techniques to model the variability of family members and to customize the business workflow of components. Our approach is to provide formal specification on the component variability, and to define techniques to customize them by means of the formalism.

• Journal of Satellite, Information and Communications
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• v.11 no.4
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• pp.44-47
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• 2016

In these days, interest of systems and services using TVWS(TV White Space) are increased, communication systems and services for TVWS have been actively studied. The unoccupied frequency in TVWS is different according to the geographical location and the time of day. RF systems having a frequency tunable bandpass filter operated in TVWS could be efficiently used. In this paper, a frequency tunable bandpass filter operated in 470 ~ 698MHz is designed and implemented. In consideration of simple control and physical size, the tunable bandpass filter is designed with 2-pole. The implemented tunable bandpass filter has the operating frequency band of 470 ~ 698MHz with control voltages of 1.58 ~ 3.93V, the insertion loss of maximum 4.78dB and the return loss of below 10dB. The implemented frequency tunable bandpass filter can be directly used in the RF receiver for TVWS and the design procedures could be used for developing a high power tunable bandpass filter as the basic research data.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.68-74
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• 2001

A design and implementation method for the UHF-band(800MHz) variable attenuator using the 3dB coupler is proposed. The 90 degree, 3-dB Coupler is used for the variable attenuator. The principal theory for the 3-dB coupler is introduced. The 3-dB Coupler is designed by the mathematical analysis and a computer simulation tool. A PIN diode is used for the variable resistor at UHF-band. The variable attenuator using the 3-dB coupler and the PIN diode is designed and implemented. The measured results for the variable attenuator by a network analyzer show that the insertion loss is below -l0dB, and the continuous variable attenuation range is about 10dB.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.720-725
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• 2013

This paper has presented that fringing-electric fields enhanced by a finger-type electrode can improve the tunability of the tunable capacitor. Its top electrodes with different area and line width are designed in types of the finger for a long conducting perimeter. The tunable varactors were fabricated on a quartz substrate employing a multi-layer dielectric of a para/ferro/para-electric thin film. Compared to the conventional capacitor, finger-type capacitors are analyzed in terms of effective capacitance and tunablility. Their effective capacitance and tunability of the varactors with the long perimeter increase 24~40 % and 7~12 %, respectively, due to enhanced fringing electric fields from 1 to 2.5 GHz.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.501-503
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• 2000

컴포넌트가 보편화되고 있는 현 시점에서 컴포넌트의 사용은 증가하고 있다. 이러한 컴포넌트들을 효과적으로 재사용하기 위해서는 컴포넌트 설계와 재사용의 올바른 분석과 설계가 요구된다. 재사용의 요구사랑을 만족하기 위해서 컴포넌트의 설계시에 발생할 수 있는 기능과 적합성의 불일치를 줄이고자하는 연구가 활발히 진행되고 있다. 본 논문에서는 공통성과 가변성 분석을 하기 위하여 도메인의 특성이 서비스 중심적인 관점인 경우에 대하여 접근을 했다. 이를 위하여 인터페이스의 추출이 선행되어야 하고, 추출된 인터페이스를 중심으로 두 도메인에 존재하는 공통성과 가변성을 추출하였다.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2002.12a
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• pp.153-157
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• 2002

일반적으로 가변구조제어는 외란과 변수 변화에 대해 강인한 특성을 가지지만 제어기 설계자는 이러한 값들에 대한 상한 값과 하한 값을 알아야한다. 그러나 때로는 이러한 상한 값과 하한 값을 얻는다는 것은 쉽지가 않다. 이에 반해 퍼지제어기는 외란과 변수 변화에 대한 제어기 설계에 있어서 효과적인 방법을 제공한다. 따라서 퍼지제어기와 가변구조제어기가 가지는 장점들을 결합하는 연구가 진행되어져 왔다. 본 논문에서는 리칭페이저가 존재하는 기존의 슬라이딩모드제어기를 이용하는 방법 대신 리칭페이저를 제거하여 전 구간 강인한 적응 퍼지 가변구조제어기를 설계하였다. 제안된 제어 알고리듬은 BLDC 전동기의 위치제어기로 사용하였으며, 그 타당성을 입증하였다.

• Ecology and Resilient Infrastructure
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• v.9 no.4
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• pp.207-217
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• 2022

The purpose of this study was to understand and develop various environmental designs to play a key roles in urban design, so that public green spaces remain vital with future changes. Variability in space, ecology, and society were analyzed based on research of variable environmental spaces in 11 selected studies conducted locally and abroad since the 2010s. Moreover, landscape characteristics, design methods, and design strategies were analyzed accordingly for each case. The results of the study showed that variability in landscapes provided various possibilities for spatial change and satisfied people's functional needs for spatial use. In addition, variable environmental design greatly compensated for the defects by solving the issues associated with fixed landscapes by increasing the flexibility of use and adaptability to the environment. This study showed that variable design is applicable to public green spaces; environmental stress; and variability in architecture, the environment, and landscaping, and it contributes to enhancing the sustainability and resilience of the environment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.5
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• pp.1649-1656
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• 1991

본 연구에서는 가변구조제어에 의한 조준경 고각 안정화를 모색하였다. 이 를 위해 조준경 고각 안정화 시스템의 운동 방정식을 이용하여 가변구조제어기를 설계 하였으며 방정식을 이용하여 가변구조제어기를 설계하였으며 실제 주행시험결과 측정 된 차량의 각속도를 외란으로 사용하여 컴퓨터 시뮬레이션하여 가변구조제어에 의한 조준경 고각 안정화가 동적안정도를 충족시킴을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10b
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• pp.277-279
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• 2003

컴포넌트 기반 개발은 재사용 단위의 컴포넌트를 사용하여 소프트웨어의 중복개발을 지양하고 시스템을 효율적으로 개발한다. 또한 인터페이스를 통해 컴포넌트 배치시 내부의 수정없이 사용자의 요구에 맞게 컴포넌트를 특화하는 장치를 제공한다. 본 논문에서는 컴포넌트 가변성(Variability)을 위한 컴포넌트 Required 인터페이스를 제시한다. 분석단계에서 컴포넌트의 공통성 및 가변성 식별이 이루어졌음을 가정하고, 분석단계의 산출물인 '가변성 식별 테이블'을 수집하여 가변성을 위한 오퍼레이션 식별 및 인터페이스를 정의한다. 또한 컴포넌트 Requited 인터페이스 명세서를 제공한다. 따라서 제시된 기법은 Required 인터페이스를 구성하는 오퍼레이션의 식별부터 명세까지 체계적인 Required 인터페이스의 설계 프로세스를 제시하여 블랙박스 컴포넌트의 가변성 설정을 위한 실용적인 Required 인터페이스의 기반이 된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.8 no.3
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• pp.96-104
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• 1983

In wire transmission systems using a coaxial cable or cable pair, the cable loss caused by the transmission characteristic of the cable varies depending on the length of the cables or variation in the ambient temperature, and usually takes the form close to a $\sqrt f$ characteristic. In order to compensiate for such loss, an actove variable automatic equalizer with a tandam combination of feedback and feedforward was presented. The automatic equalizer to be described here overcomes many of the disadbantages associated with the conventional passive variable equalizers, which include the need for inducters, a complex design procedure, and incompatibility with modern dldctronic control systems that are very complicated. This design has advanatges over other active variable equalizer design and it is especially applicable to precision equalization at frequencies bellow 1MHz.