• Current Optics and Photonics
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• v.5 no.2
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• pp.134-140
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• 2021

In this paper, I introduce a novel design method of a high performance nanophotonic beam deflector providing broadband operation, large active tunability, and signal efficiency, simultaneously. By combining thermo-optically tunable vanadium dioxide nano-ridges and a metallic mirror, reconfigurable local optical phase of reflected diffraction beams can be engineered in a desired manner over broad bandwidth. The active metagrating deflectors are systematically designed for tunable deflection of reflection beams according to the thermal phase-change of vanadium dioxide nano-ridges. Moreover, by multiplexing the phase-change supercells, a robust design of actively tunable beam splitter is also verified numerically. It is expected that the proposed intuitive and simple design method would contribute to development of next-generation optical interconnects and spatial light modulators with high performances. The author also envisions that this study would be fruitful for modern holographic displays and three-dimensional depth sensing technologies.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.19-21
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• 2008

The purpose of this paper is the optimal design of a single-phase LSPM(Line-Start Permanent Magnet Motor). A single-phase LSPM has a permanent magnet in the rotor that is same as induction motor. For that reason, magnet is operated by breaking torque in starting region and alignment torque in driving region. Therefore, we need the design process considering the trade-off relationship. In this paper, we propose the design process of a single-phase LSPM for a high starting torque and efficiency with equivalent circuit and FEM. And we use Taguchi Method for considering tolerance in manufacture. Finally, we compared the LSPM that is designed in this paper and conventional induction motor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.1
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• pp.29-35
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• 2014

The purpose of this paper is the rotor design of a single-phase LSPM(Line-start permanent magnet) motor. A single-phase LSPM motor has a permanent magnet in the rotor that is same as induction motor. For that reason, magnet is operated by breaking torque in starting region and alignment torque in driving region. Therefore, we need the design process considering the trade-off relationship. In this paper, we propose the design process of a single-phase LSPM motor for a high starting torque and efficiency with FEM. And we use Taguchi Method for considering tolerance in manufacture. Finally, we compared the LSPM motor that is designed in this paper and conventional induction motor.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.684-696
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• 2018

The mission in missile systems can be conducted with multiple phases according to the characteristics of the systems and the targets. The safeguarded multi-phase mission includes a safeguarded phase before launch for considering the safety of operators in unexpected squib activation. However, the safeguard function should be disabled after launch to complete the mission. Therefore, the squib system needs to be selectively activated according to the phases. This paper presents a selective squib activation and check circuit design for safeguarded multi-phase missions in missile systems. The presented circuit design was implemented with various electronic components including a field-programmable gate array(FPGA). Its functions and performance were validated by both many ground tests and several flight tests.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.370-379
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• 2015

Handling constantly evolving configurations of aircraft can be inefficient and frustrating to design engineers, especially true in the early design phase when many design parameters are changeable throughout trade-off studies. In this paper, a physics-based design framework using parametric modeling is introduced, which is designated as DIAMOND/AIRCRAFT and developed for structural design of transport aircraft in the conceptual and preliminary design phase. DIAMOND/AIRCRAFT can relieve the burden of labor-intensive and time-consuming configuration changes with powerful parametric modeling techniques that can manipulate ever-changing geometric parameters for external layout of design alternatives. Furthermore, the design framework is capable of generating FE model in an automated fashion based on the internal structural layout, basically a set of design parameters describing the structural members in terms of their physical properties such as location, spacing and quantities. The design framework performs structural sizing using the FE model including both primary and secondary structural levels. This physics-based approach improves the accuracy of weight estimation significantly as compared with empirical methods. In this study, combining a physics-based model with parameter modeling techniques delivers a high-fidelity design framework, remarkably expediting otherwise slow and tedious design process of the early design phase.

• Journal of the Korean Society of Systems Engineering
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• v.14 no.1
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• pp.72-82
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• 2018

Generally speaking, because of complexity of engineering process, the systems engineering may be not easy to understand clearly and not easy to perform also. The status of systems engineering infrastructure of the some Korean industry is not matured yet, i.e., the systems engineering process, method, tool and environment is not implemented consistently within the steel making industry. These difficulties are more severe at the concept and basic design phase than the detail design phase relatively. Korean industry has lots of development project for the precedented systems and usually has matured domain knowledge for the precedented systems. Even though there is a mature domain knowledge of the precedented systems, the development project will lead to failure under the condition of engineering system is not well equipped. For the project success, it is very important to have a proper engineering execution system especially for the concept design and basic phase, which has a high abstraction and a large influence on the whole project. This paper proposes a minimized design process that can be easily applied to the concept and basic design phase of the precedented systems, instead of complex system engineering processes. This paper also proposes the application case of the minimized design process and methods for a Blast Furnace System.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.5
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• pp.541-546
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• 2008

A novel, simple and broadband $90^{\circ}$ phase shifter was proposed and fabricated by the LTCC process. It is composed of a $180^{\circ}$ transmission line between two $90^{\circ}$ shorted transmission lines. Design equations for the proposed $90^{\circ}$ phase shifter are derived by the method of admittance parameter analysis. Based on design equations, $90^{\circ}$ phase shifter was designed and fabricated to operate in the C-band with ${\pm}2^{\circ}$ of phase deviation.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.158-164
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• 2008

This project investigates an optimum phase design implementing a 256 phase Opto-ULSI processor for multi-function capable optical networks. The design of an 8 phase processor is already in construction and will provide the initial base for experimentation and characterization. The challenge is to be able to compensate for the non-linearity of the liquid crystal, find an optimum phase, and implement a larger scale Opto-ULSI processor. This research is oriented around the initial development of an 8 phase Opto-ULSI processor that implements a Beam Steering(BS) Opto-ULSI processor(OUP) for integrated intelligent photonic system(IIPS), while investigating the optimal phase characteristics and developing compensation for the non-linearity of liquid crystal.

• Journal of the Korea Computer Industry Society
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• v.5 no.2
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• pp.261-268
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• 2004

This study to design an optimum phase implementing a 256 phase Opto-ULSI processor for multi-function capable optical networks. The design of an 8 phase processor is already in construction and will provide the Initial base for experimentation and characterisation. The challenge is to be able to compensate for the non-linearity of the liquid crystal, find an optimum phase, and implement a larger scale Opto-ULSI processor. This research is oriented around the initial development of an 8 phase Opto-ULSI processor that implements a Beam Steering (BS) Opto-ULSI processor (OUP) for integrated intelligent photonic system (IIPS), while investigating the optimal phase characteristics and developing compensation for the non-linearity of liquid crystal.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.1154-1157
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• 2005

This report is to do design management for constructability review of high quality exposed concrete, which is used increasingly in recent. To secure systematic management at design phase, we reviewed each definition and work at each design phase, we define high quality exposed concrete, a part of architectural concrete, as "an exposed concrete which has well ordered joint & is in pursuit of smooth surface." We reviewed requirements and influential factor to obtain High quality finishing surface and compared construction process of high quality exposed concrete with that of other finishing method. Management method at each design phase for constructability review to meet additional works and requirements is presented.