• Journal of Power Electronics
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• 제18권1호
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• pp.309-322
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• 2018

The technology of inductive power transfer has been proved to be a promising solution in many applications especially in electric vehicle (EV) charging systems, due to its features of safety and convenience. However, loosely coupled transformers lead to the system efficiency not coming up to the expectation at the present time. Therefore, at first, the magnetic core losses are calculated with a novel magnetic-circuit model instead of the commonly used finite-element-method (FEM) simulations. The parameters in the model can be obtained with a one-time FEM simulation, which makes the calculation process expeditious. When compared with traditional methods, the model proposed in the paper is much less time-consuming and relatively accurate. These merits have been verified by experimental results. Furthermore, with the proposed loss calculation model, the system is optimized by parameter sweeping, such as the operating frequency and winding turns. Specifically, rather than a predesigned switching frequency, a more efficiency-optimized frequency for the series-parallel (SP) compensation topology is detected and a detailed investigation has been presented accordingly. The optimized system is capable of an efficiency that is greater than 93% at a coil separation distance of 200mm and coil dimensions of $600mm{\times}400mm$.

• 기술혁신연구
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• 제10권1호
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• pp.148-173
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• 2002

This study examines the impact of the Internet on the organizational innovation. With the introduction of digital technology, the entire organizational process and structure is now being restructured. The purpose of this study is to develop a framework to help classify the organizational innovations and understand organizational innovation processes. This study suggests that the wide diffusion of digital technology has affected the modularization of the organizational routines and processes. The modularization of knowledge and organization give rise to a new organizational architecture, a modular architecture. In the Fordist regime, the characteristics of organizations were depicted as vertically integrated and tightly coupled system. The organizational processes and routines were tightly linked and integrated. However, the diffusion of Internet, which has a tendency to disassemble this tightly coupled system, has resulted in the emergence of loosely coupled and vertically disintegrated system. Eventually the modular architectures are emerging as a new organizational paradigm in the post-Fordist regime. In this study, the modes of organizational innovation is classified as follows. If the organizational innovation enhances both existing organizational components and tile tightly coupled architecture, it is incremental innovation (Mode 1): if it destroys both existing components and the tightly coupled architecture, it is radical innovation (Mode 4): however if only the tightly coupled architecture is transformed into the modular architecture and the codification of organizational component is enhanced, the innovation is architectural (Mode 3). The last one is component innovation (Mode 2), in which existing organizational components are destroyed but tightly coupled architecture is enhanced. It is argued that the organizational innovation process follows Mode I$\longrightarrow$ Mode II $\longrightarrow$ Mode III $\longrightarrow$ Mode IV in order.

• 제어로봇시스템학회논문지
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• 제13권7호
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• pp.688-693
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• 2007

The INS/GPS integration system is designed by employing an adaptive filter that can estimate the measurement noise variance using the residual of the filter. To verify the efficiency of the proposed loosely-coupled INS/GPS integration system, simulation is performed by assuming that GPS information has large position errors. Simulation results show that the proposed integration system with the adaptive filter is more effective in estimating the position and attitude errors than those with the Extended Kalman Filter.

• 한국시뮬레이션학회논문지
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• 제16권4호
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• pp.33-41
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• 2007

서비스 지향 아키텍처는 하나의 실체가 다른 하나의 실체를 대신해 단위 작업을 수행하도록 하는 방식으로 두 개의 컴퓨팅 실체가 상호작용 하는 방법을 정의한다. 이 단위 작업은 "서비스"라고 지칭되며, 이 서비스 상호작용들은 독립적이고 느슨한 결합을 가져야 한다. SOA의 이러한 특징인 느슨한 결합과, 높은 상호운영성의 효과는 서로 다른 이용자들이 서로 다른 방식으로 서비스와 의사소통을 하기 위해 얼마나 유연한 메시지 통신이 가능한가에 따라 결정된다. 본 논문에서는 .NET Framework를 이용한 WCF 기반의 메시징 프레임워크와 통합된 데이터 표현 방식을 이용하여 서비스 지향 아키텍처를 기반으로 한 웹 서비스 애플리케이션과 일반적인 웹 서비스에 대해 애플리케이션의 응답 성능 및 시스템의 안정성과 성능 지수를 비교 분석하였으며 그 결과를 통하여 WCF를 이용한 SOA환경의 웹 서비스가 가지는 장점을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.6-7
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• 2019

본 논문에서는 양방향 전력 전송을 가능케 해주는 Dual-active-bridge (DAB) 컨버터에서, 고주파 변압기 대신 무선 전력 전송 코일을 이용한 시스템을 제안한다. 기존의 DAB 컨버터에서 주로 사용되는 고주파 변압기는 Core-type 또는 shell-type으로 만들어지며, 1차 측 권선과 2차 측 권선이 자기적으로 강하게 결합되어 높은 전력 전달 효율을 가지도록 만든다. 이런 DAB 컨버터를 직/병렬 연결해 MV-DC to LV-DC로 변환하는 반도체 변압기 등을 구성할 때, 1차 측 권선과 2차 측 권선 사이에는 절연 문제와 1차 측 스위치 회로와 2차 측 스위치 회로, 그리고 고주파 변압기가 각각 따로 절연해야 하는 문제점이 있다. 본 논문에서 제안하는 DAB 컨버터는 1차 측과 2차 측이 수 cm 이격되어 있어 1차 측과 2차 측 사이의 자기적 결합이 굉장히 약하다. 따라서 1차 측과 2차 측 코일을 커패시터로 공진시켜 전력을 전달하는 무선전력전송(Loosely Coupled Inductive Wireless Power Transfer)을 이용한다. 무선전력전송의 공진 topology는 Parallel-Series로 선택했고, impedance transformation 회로를 추가했다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 D
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• pp.2433-2435
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• 2000

Inertial Navigation System(INS) provides short-term accurate navigation solution but its error grows with time due to integration characteristics. Meanwhile, Global Positioning System(GPS) provides long-term stable solution but it has poor error characteristics in high dynamic region. So for its synergistic relationship, an integrated INS/GPS systems has been widely used as an advanced navigation system. Generally, two kinds of integration method are used. One is loosely coupled mode which uses GPS-derived position and velocity as measurements in an integrated Kalman filter. The other is tightly coupled one which uses pseudorange and pseudorange rate as Kalman filter measurements. In this paper the system error models and observation models for two kinds of integrated systems are derived, respectively, and their performance are compared through Monte-Carlo simulations.

• 경영과학
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• 제15권2호
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• pp.177-200
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• 1998

One of organization's generic functions is the interpretation of events to carry out decision-making activities. In intelligent Data Interpretation System(IDIS), Interpreting is computationally modeled as classification of new data into categories having similar features. We define the Extensional Object Model(ExOM) as a formalism for IDIS. In ExOM, objects and categories are loosely coupled to provide flexibility for both object description and category definition in data gathering and interpretation process. Objects are classified inductively based on exemplars of categories as well as deductively based on category structures.

• Bioinformatics and Biosystems
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• 제1권1호
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• pp.38-45
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• 2006

본 논문은 베이지안 네트워크를 기반으로 대규모 유전자 상호작용 네트워크를 추론하기 위한 클라이언트-서버 시스템 구조를 제시한다. 유전체 수준(genome-wide)의 대규모 유전자 상호작용 네트워크를 베이지안 네트워크 형태로 추론하기 위해서는 병렬 서버를 이용하더라도 통상 수십시간이 소요된다. 따라서, 일반적인 대화형(interactive) 독자(standalone) 시스템 구조보다는 배치형(batch) 분산(distributed) 시스템 구조가 적합하다. 본 논문에서는 그와 같은 상황에 적합한 느슨한 연결의 (loosely-coupled) 클라이언트-서버 시스템을 구현할 결과를 기술한다. 유전자 상호작용 네트워크 추론은 크게 두 단계로 나누어진다. 첫째로, 생물주석정보(biological annotation)과 유전자 발현정보(expression data)를 사용하여, 전체 유전자 집단을 서로 중복이 가능한 모듈들로 나누며, 둘째로, 각각의 모듈들에 대해 독립적인 베이지안 학습을 수행하여 추론결과를 얻고, 각 모듈들이 공통으로 포함하는 유전자를 사용하여 각 모듈의 추론결과들을 하나로 통합한다.

• ETRI Journal
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• 제45권5호
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• pp.758-767
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• 2023

In this study, we introduce a loosely coupled relative position estimation method that utilizes a decentralized ultrawideband (UWB), Global Navigation Support System and inertial navigation system for flight controllers (FCs). Key obstacles to multidrone collaboration include relative position errors and the absence of communication devices. To address this, we provide an extended Kalman filter-based algorithm and module that correct distance errors by fusing UWB data acquired through random communications. Via simulations, we confirm the feasibility of the algorithm and verify its distance error correction performance according to the amount of communications. Real-world tests confirm the algorithm's effectiveness on FCs and the potential for multidrone collaboration in real environments. This method can be used to correct relative multidrone positions during collaborative transportation and simultaneous localization and mapping applications.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권5호
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• pp.400-407
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• 2005

Reverse engineering is defined as the process where the internal structures and dynamics of a given system are inferred and analyzed from external observations and relevant knowledge. The first part of this paper surveys existing techniques for biosystem reverse engineering. Network structure inference techniques such as Correlation Matrix Construction (CMC), Boolean network and Bayesian network-based methods are explained. After the numeric and logical simulation techniques are briefly described, several representative working software tools were introduced. The second part presents our component-based software architecture for biosystem reverse engineering. After three design principles are established, a loosely coupled federation architecture consisting of 11 autonomous components is proposed along with their respective functions.