• Journal of Power Electronics
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• 제18권1호
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• pp.185-194
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• 2018

Interaction among multiple grid-connected inverters has a negative impact on the stable operations and power quality of a power grid. The interrelated influences of inverter inductor-capacitor-inductor filters constitute a high-order power network, and consequently, excite complex resonances at various frequencies. This study first establishes a micro-grid admittance matrix, in which inverters use deadbeat control. Multiple resonances can then be evaluated via modal analysis. For the active damping method applied to deadbeat control, the sampling frequency and the stable domain of the virtual damping ratio are also presented by analyzing system stability in the discrete domain. Simulation and experimental results confirm the efficiency of modal analysis and stable domain calculation in multi-inverter grid-connected systems.

• 한국멀티미디어학회논문지
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• 제12권12호
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• pp.1787-1795
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• 2009

This paper describes an automation of architectural design processes and the direction between this automation and robotic system in building construction using the concept of the object-oriented design in architecture. The research starts from the premise that many computer-aided design systems are mostly aimed at serving as drawing tools which are used only after a design formal solution has already been established by the architect. If the computer is well applied to the architectural design process, many positive things such as standardization of design detail, increasing productivity and collaboration, minimizing construction costs etc. can be done. To support an early design solution in the computer-based environment, the proposed automation was developed and tested in a real building project, using the object-oriented design concept such as product model. This design automation gives various design alternatives from the early design phase to the final stage of design details, according to musical harmony. This paper shows how architectural design process can be automated and how the data of the applied architectural design can be integrated into product model environment, in relation to robotic system in building construction.

• Current Optics and Photonics
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• 제2권6호
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• pp.576-581
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• 2018

A new approach for identification of a microwave frequency using an integrated optical waveguide chip, combined with a phase modulator (PM) and two microring resonators (MRRs), is proposed, theoretically deduced, and verified. By wavelength tuning to set the PM under the condition of a double side band (DSB), the measurement range can be started from the dc component, and the measurement range and response slope can be adjusted by designing the radius and transmission coefficient of the MRR. Simulations reveal that the amplitude comparison function (ACF) has a monotonic relationship from dc to 32.5 GHz, with a response slope of 5.15 dB under conditions of DSB modulation, when the radius values, transmission coefficients, and the loss factors are designed respectively as $R_1=400{\mu}m$, $R_2=600{\mu}m$, $t_1=t_2=0.63$, and ${\gamma}_1={\gamma}_2=0.66$. Theoretical calculations and simulation results both indicate that this new approach has the potential to be used for measuring microwave frequencies, with the advantages of compact structure and superior reconfigurability.

• Journal of Power Electronics
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• 제19권4호
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• pp.989-999
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• 2019

This paper proposes a fault-tolerant control strategy with finite control set model predictive control (FCS-MPC) based on hierarchical optimization for five-level H-bridge neutral-point-clamped (5L-HNPC) inverter-fed induction motor drives. Fault-tolerant operation is analyzed, and the fault-tolerant control algorithm is improved. Adopting FCS-MPC based on hierarchical optimization, where the voltage is used as the controlled objective, called model predictive voltage control (MPVC), the postfault controller is simplified as a two layer control. The first layer is the voltage jump limit, and the second layer is the voltage following control, which adopts the optimal control strategy to ensure the current following performance and uniqueness of the optimal solution. Finally, simulation and experimental results verify that 5L-HNPC inverter-fed induction motor drives have strong fault tolerant capability and that the FCS-MPVC based on hierarchical optimization is feasible.

• Journal of Information Processing Systems
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• 제18권5호
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• pp.688-700
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• 2022

A composite bionic soft gripper integrated with electromagnets and magneto-active elastomers is designed by combining the structure of the human hand and the snake's behavior of enhancing friction by actively adjusting the scales. A silicon-based polymer containing magnetized hard magnetic particles is proposed as a soft finger, and it can be reversibly bent by adjusting the magnetic field. Experiments show that the length, width, and height of rectangular soft fingers and the volume ratio of neodymium-iron-boron have different effects on bending angle. The flexible fingers with 20 vol% are the most efficient, which can bend to 90° when the magnetic field is 22 mT. The flexible gripper with four fingers can pick up 10.51 g of objects at the magnetic field of 105 mT. In addition, this composite bionic soft gripper has excellent magnetron performance, and it can change surface like snakes and operate like human hands. This research may help develop soft devices for magnetic field control and try to provide new solutions for soft grasping.

• International Journal of Computer Science & Network Security
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• 제21권7호
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• pp.233-240
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• 2021

The majority of the Web's success can be related to its productivity and flexibility. Web Services (WSs) have the means to create new patterns for the delivery of software capabilities. The WS easily provides the use of existing components available via the Internet. WSs are a new trend that shares ubiquitous systems with others, so the popularity of the Web is increased day by day with their associated systems. This paper will explore and adopt the possibility of developing a technique that will automate instructors' scheduling of timetables within a Web services environment. This technique has an advantage that facilitates users to reduce the time cost and effort by reducing errors and costs for institutes. Providing dependable tables to avoid mistakes related to instituting schedules is ensured by an automated repetitive manual procedure. Automated systems are increasingly developed based on organizations and their customers. Still, the setting's difficulty of automation systems increases to rise as the system architecture and applications must accomplish various requirements and specifications of ever-demanding project scenarios. The automation system is composed of an operating system, platforms, devices, machines, control system, and information technology. This architecture provides more productivity and optimized services. The main purpose of this paper is to apply an automation system to enhance both quality and productivity. This paper also covers an agile method of proving an automation system by Finite State Machine (FSM) and Attributed Graph Grammar (AGG) tool.

• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.569-574
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• 2005

This paper presents the core technology of Construction Business Process Automation to model and automate construction business processes. Business Process Reengineering (BPR) and Automation (BPA) have been recognized as one of the important aspects in construction business management. However, BPR requires a lot of efforts to identify, document, implement, execute, maintain, and keep track thousands of business processes to deliver a project. Moreover, existing BPA technologies used in existing Enterprise Resource Planning (ERP) systems do not lend themselves to effective scalability for construction business process management. Application of Workflow and Object Technologies would be quite effective in implementing a scalable enterprise application for construction community. This paper present the technologies and methodologies for automating construction business processes by addressing how: 1) Automated construction management tasks are developed as software components, 2) The process modeling is facilitated by dragging-and dropping task components in a network, 3) Raising business requests and instantiating corresponding process instances are delivered, and 4) Business process instances are executed by using workflow technology based on real-time simulation engine. This paper presents how the construction business process automation is achieved by using equipment reservation and cancellation processes simplified intentionally.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.421-422
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• 2020

Hardware In-the-Loop simulation(HIL)은 실제 하드웨어 시스템을 실시간 모사할 수 있는 시뮬레이션 장비로 연구 및 개발 기간의 단축, 비용저감 등의 장점을 앞세워 다양한 전력전자 분야에 사용되고 있다. 실제 하드웨어를 그대로 모사하는 것이 HIL의 목적이기 때문에 HIL 장비는 검증의 실시간성과 출력된 결과의 정확성이 무엇보다도 중요하다고 할 수 있다. 하지만 코어간의 데이터를 주고받는 과정에서 HIL의 연산 속도 및 정확성을 저해하는 요인들이 발생하게 된다. 본 연구에서는 HIL 장비를 이용해 복잡한 시스템을 구현함에 있어서 연산속도 및 정확성을 저해하는 요인들을 찾아내고 이를 해결하기 위한 방법을 제안한다. 제안된 연산속도 개선 및 정확성 개선 방법의 타당성은 프로세서의 연산 속도 변화량, HIL 및 시험 결과 파형의 비교 분석을 통해 검증되었다.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.336-343
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• 2022

Industrial robotic arms are widely adopted in numerous industries for manufacturing automation under factory settings, which eliminates the limitations of manual labor and provides significant productivity and quality benefits. The U.S. modular construction industry, despite having similar controlled factory environments, still heavily relies on manual labor. Thus, this study investigates the U.S., Canada, and Europe-based leading modular construction companies and research labs implementing industrial robotic arms for manufacturing automation. The investigation mainly considered the current research scope, industry state, and constraints, as well as identifying the types and specifications of the robotic arms in use. First, the study investigated well-recognized modular building associations, the Modular Building Institute (MBI), and renowned architecture design magazine, Dezeen to gather industry updates. The authors discovered one university lab and a few companies that adopted Switzerland-based robotic arms, ABB. Researching ABB robotics led to the discovery of ABB's competitor, Germany-based KUKA robotic arms. Consequently, research extended to the companies and labs adopting KUKA models. In total, this study has identified seven modular companies and four research labs. All companies employed robotic arms and gantry robot combinations in a production-line-like system for partial automation, and some adopted design standardization for optimization. The common goal among the labs was to achieve greater flexibility and full automation with robotic arms. This study will help companies better implement robotic arm automation by providing recommendations from investigating its current industry status.

• 한국항해항만학회지
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• 제42권3호
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• pp.217-226
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• 2018

세계 주요 컨테이너터미널들은 중심항만으로 성장하기 위해 치열한 경쟁 속에서 우위를 선점하기 위해 자동화 시설을 확충하는데 노력하고 있다. 최근 컨테이너터미널에서 자동화 시스템의 완전 통합을 위해 시스템 설계 및 개발이 진행되고 있다. 이는 컨테이너터미널의 야드 작업 효율성을 높이는 데 집중 할 수 있고 다른 컨테이너터미널 운영 프로세스와 통합이 쉬워지기 때문이다. 컨테이너터미널에서 자동화 시스템은 고객에게 더 나은 서비스를 제공하고 수익성을 향상시키는 데 필수적이다. 컨테이너터미널 가동을 보다 효율적으로 운영하고 결과적으로 생산성을 높이려면 Container Handling Equipment(CHE)의 실시간 위치와 상태확인이 요구되고 있다. 본 연구는 컨테이너터미널에 DGPS를 이용하여 컨테이너터미널 자동화 장비의 실시간 위치와 상태를 확인하고 자동화 시스템을 실제 개발, 적용, 운영하는 컨테이너터미널 야드 이송장비 자동화 시스템의 구성요소와 기능을 살펴본 후 실제로 적용하여 기존 야드 이송장비 시스템과 야드 이송장비 자동화 시스템을 비교 분석 및 적용방안에 대해 제시하였다. 또한, 컨테이너터미널의 핵심 장비인 이송장비의 효율적인 운영을 위해서 최적의 야드 이송 장비 자동화 시스템을 이용하게 되면 컨테이너터미널의 생산성 및 이송장비의 효율성을 좀 더 높일 수 있다는 걸을 알 수 있었다.