• Journal of Power Electronics
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• v.16 no.4
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• pp.1396-1406
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• 2016

A novel controller design is presented for the recently proposed electric springs (ESs). The dynamic modeling is analyzed first, and the initial Bode diagram is derived from the s-domain transfer function in the open loop. The design objective is set according to the characteristics of a minimum phase system. Step-by-step optimizations of the Bode diagram are provided to illustrate the proposed controller, the design of which is different from the classical multistage leading/lagging design. The final controller is the accumulation of the transfer function at each step. With the controller and the recently proposed δ control, the critical load voltage can be regulated to follow the desired waveform precisely while the fluctuations and distortions of the input voltage are passed to the non-critical loads. Frequency responses at any point can be modified in the Bode diagram. The results of the modeling and controller design are validated via simulations. Hardware and software designs are provided. A digital phase locked loop is realized with the platform of a digital signal processor. The effectiveness of the proposed control is also validated by experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.10
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• pp.1077-1086
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• 2014

We propose a design method of a Rotman lens for curved array antenna applicable to conformal array. In this paper, design equations are derived to obtain an array curve, transmission line lengths of a Rotman lens in conjunction with a curved array antenna, and the phase error of a Rotman lens based on these design equations is minimized through the beam curve optimization procedure and the refocusing procedure. Rotman lenses designed by the proposed design equations and design procedures still maintain 3 focal points, can feed a convex or concave array antenna with circular curve, parabolic curve, V-shaped curve, etc as well as a straight line array antenna, and have minimal phase error.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.65-72
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• 2009

Laser interferometry is widely used as a measuring system in many fields because of its high resolution and its ability to measure a broad area in real-time all at once. In conventional laser interferometry, for example out-of-plane ESPI (Electronic Speckle Pattern Interferometry), in plane ESPI, shearography and holography, it uses PZT or other components as a phase shift instrumentation to extract 3-D deformation data, vibration mode and others. However, in most cases PZT has some disadvantages, which include nonlinear errors and limited time of use. In the present study, a new type of laser interferometry using a laser diode is proposed. Using Laser Diode Sinusoidal Phase Modulating (LD-SPM) interferometry, the phase modulation can be directly modulated by controlling the laser diode injection current thereby eliminating the need for PZT and its components. This makes the interferometry more compact. This paper reports on a new approach to the LD (Laser Diode) Modulating interferometry that involves four-frame phase shift method. This study proposes a four-frame phase mapping algorithm, which was developed to have a guaranteed application, to stabilize the system in the field and to be a user-friendly GUI. In this paper, the theory for LD wavelength modulation and sinusoidal phase modulation of LD modulating interferometry is shown. Using modulating laser and research of measurement algorithm does comparison with existent ESPI measurement algorithm. Algorithm measures using GPIB communication through most LabVIEW 8.2. GPIB communication does alteration through PC. Transformation of measurement object measures through modulating laser algorithm that develops. Comparison of algorithm of modulating laser developed newly with existent PZT algorithm compares transformation price through 3-D. Comparison of 4-frame phase mapping, unwrapping, 3-D is then introduced.

• Journal of Institute of Control, Robotics and Systems
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• v.18 no.6
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• pp.546-554
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• 2012

This paper suggests a design method of an improved phase control loop for tracking resonant frequency of solid type precision resonant gyroscope. In general, a low cost MEMS gyroscope adapts the automatic gain control loops by taking a velocity feedback configuration. This control technique for controlling the resonance amplitude shows a stable performance. But in terms of resonant frequency tracking, this technique shows an unreliable performance due to phase errors because the AGC method cannot provide an active phase control capability. For the resonance control loop design of a solid type precision resonant gyroscope, this paper presents a phase domain control loop based on linear PLL (Phase Locked Loop). In particular, phase control loop is exploited using a higher order PLL loop filter by extending the first order active PI (Proportion-Integral) filter. For the verification of the proposed loop design, a hemispherical resonant gyroscope is considered. Numerical simulation result demonstrates that the control loop shows a robust performance against initial resonant frequency gap between resonator and voltage control oscillator. Also it is verified that the designed loop achieves a stable oscillation even under the initial frequency gap condition of about 25 Hz, which amounts to about 1% of the natural frequency of a conventional resonant gyroscope.

• Journal of the Korean Institute of Gas
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• v.21 no.3
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• pp.1-8
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• 2017

The purpose of this study is to suggest the rupture disk design(size) and application at the two phase(gas-liquid) flow by runaway reaction at batch reactor. The definition of runaway reaction is abnormally exothermic reaction by the uncontrolled cooling water or deviated operating condition. As a result, the temperature of reactor is rapidly increasing. The causes of runaway reaction are either self-heating reaction or sleeper reaction. General methods of rupture disk size or safety valve are not suitable in the runaway reaction, because of temperature and pressure increasing rapidly in the reactor and the phases of relieving fluid is 2-phase flow. This study case of the reactor incident, the depressurization system such as safety valve and vent installed, however, the system did not relieved the pressure of reactor suitably. The orifice size of the safety valve were designed too small because the size had not been considered the phenomena and character of reaction. The batch reactor design should be considered by referring to the possibility of runaway reaction proposed in this study and the size of rupture disk design method considering 2-phase flow.

• Archives of design research
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• v.16 no.2
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• pp.35-48
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• 2003

Home networking technology connects individual home appliances through a wired or wireless network and makes possible new functions that were impossible when they were used independently. However, the new functions must not simply be confusing arrays of functions that are possible to implement, but those absolutely necessary to the users. To develop innovative information appliances with such functions, scenarios were used and played guiding roles in suggesting new product ideas, making design mockups, and producing videos to show natural situations where the products would be used in home of the future. In the phase of suggesting new product ideas, user action scenarios in the home, generated by a team consisting of experts in the fields of cognitive engineering, user interface, computer science, cultural anthropology, interaction design, and product design, helped the team identify user needs and design factors necessary to fulfill those needs and suggest new product ideas from the design factors. In the phase of making design mockups, the procedures of using the products were described in the scenario format. Based on the scenarios the s쇼les and the user interfaces of them were designed. In the phase of producing videos, the interactions between the user and the product were embodied in the course of professional writers'arranging the scenarios of using the products for the scripts of the videos. Videos were produced to show the actual situations where the design mockups would be used in home of the future and the dynamic aspects of interaction design.

• Journal of KIBIM
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• v.5 no.4
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• pp.1-10
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• 2015

In order to apply the BIM technology effectively and efficiently during the life-cycle of project, it is important to deliver a accurate information on BIM from designer, and it should be used effectively at construction or maintenance stage. However, stakeholders have created a new BIM model at each phase in many practise adopting BIM, not used BIM generated in design stage. Because they have different purposes for using BIM, and deliver the BIM model without the sufficient explanation or application. It is necessary to define the range of usable BIM in construction phase with analyzing clearly the BIM created in design phase, and determining the difference with required BIM in construction phase. Therefore, this study propose a method for construction c

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.5
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• pp.238-242
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• 2001

In this paper, we extracted design parameters for re-entrant mode microstrip directional coupler using FE(finite element) calculations. The microstrip directional coupler suffers from a poor directivity due to effect of the inhomogeneous dielectric including both dielectric substrate and air in microstrip transmission lines. Thus, the phase velocity of even mode is not equal to that of odd mode. In order to improve the directivity of microstrip directional coupler, a novel re-entrant mode microstrip directional coupler was employed. In microstrip configuration, the high directivity can be reached by matching the even- and odd-mode effective phase velocities. Through the values of capacitance obtained from 2-dimensional FE calculations, the phase velocities for each mode and the design parameter were extracted for the proposed parallel coupled-line configuration. Based on the extracted design parameter with phase matching condition, we designed and fabricated a 30dB directional coupler at 0.85GHz. Experimental results show good performance with excellent, isolation and directivity.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.23-29
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• 2008

Most VE operation related to construction project is progressed in stage of planing or design phase, especially in case of domestic. It is encouraging fact and if you have VE process in stage of planning and design, you'll have experience a reduction of about 70% of total saving cost in which total construction process may occurred. However, recently the work of construction in overseas increase and almost is only construction-work, except planning and design process. As this reason, VE process for construction-work phase only is demanded in high necessity. VE in construction phase comes to accomplish intensively in the part which the design change does not follow, through know-how, equipment operating method and method of temporary-structure erection at the established construction-site learned, builders will be the possibility of reduction from 3% to 10% in constructive expense. This paper describes VE performing example in OO company's construction-work phase, and propose the methodology of VE performance in the phase of construction. And also it is aimed to extending VE applications into the overseas construction enterprise.

• Journal of the Korean Institute of Educational Facilities
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• v.20 no.5
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• pp.11-18
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• 2013

This study has revisited the definition and characteristics of BIM to contribute to the better understanding of this concept. For the successful application of BIM in architectural design field, it should start with public buildings like schools which can be standardized. Since a number of conditions of school design appear to suit the schematic design phase for BIM application more than do other types of building design, the viability of BIM was examined by applying parametric modeling(one of BIM's basic characteristics) to mass study in schematic design phase for the configuration of schools that adopt the variation type of subject classroom design of the $7^{th}$ National Educational Curriculum. In addition, this modeling technique was used with software of Rhino 3D and Grasshopper, which will have a linkage to environmental analysis in near future. Finally, it can be expected that the work efficiency will be maximized if BIM is going to be applied in the early design stage instead of the end stage.