• Korean Journal of Computational Design and Engineering
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• v.16 no.2
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• pp.146-155
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• 2011

As the seriousness of environmental pollution being on a rise, a low carbon and environment-friendly design for energy efficiency has been issued. With respect to energy in the construction industry, an adoption of BIM which is possible for the various energy performance assessments in the early design phase has been actively working on. In the most cases of energy performance assessment, the data compatibility from the lack of standard software and format became a problem and the improvement for data compatibility system has been needed. This study is to develop the IFC based IDF converter as a middleware which connects between BIM software and energy analysis software. For the building energy performance assessment, Energy Plus and IFC are selected for the standard energy analysis software and its file format. Parameters are organized by steps and the integrated material library is built so it is trying to reduce the existing problem of energy software interface as much as possible. The development of IDF Converter will promote the spread of related fields with increasing the BIM standard and the utilization of energy performance assessment.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.434-440
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• 2003

The exchange of model design date among heterogeneous CAD systems is a difficult task because each system has different data structures suitable for its own functions. STEP has been able to represent product information as a common computer-interpretable form that is required to remain complete and consistent when the product informant is needed to be exchanged among different computer system. However, STEP has difficult architecture in is representing point, line, curve and vectors of element, more over it can't represent geometry data of feature based models. In this study, a structure of XML document that represents geometry data of feature based models as neutral format has been developed. To use the developed XML document, a Converter has also been developed to exchange modules so that it can exchange feature based data models among heterogeneous CAD systems. Aa for evaluation of the developed XML document and Converter, Solidworks and SolidEdge are selected.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.6
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• pp.314-324
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• 2006

In recent years, having the advantages of being small, low in cost and high in efficiency, Half-wave resonant type, (having only one output diode), is used in ZVS Half-Bridge DC/DC converter. This paper presents the operation mode by multi-resonant factors in the Half-wave type multi-resonant converter with direct Buck chopper circuit operated in discontinuous current mode. To study the characteristics of a multi-resonant operation in steady-state, the characteristic impedances in each mode and safe operation-region(S.O.R) are reported. Computer simulation and experimental data are also riven to verify the theoretical results.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.650-654
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• 1999

In this paper, author describe the simulation results concerning the period doubling bifurcation route to chaos of DC/DC boost converter under current mode control to show that it is common phenomena on switching regulator when parameters are improperly chosen or continuously varied beyond the ensured region by system designer. Bifurcation diagrams of periodic orbits of inductor current and capacitor voltage of DC/DC boost converter are plotted with sampled data at moment of each clock pulse causing switching on. DC/DC boost converter studied on this paper is modelled by its state space equations as per switching condition under continuous conduction mode. Current reference signal and capacitance are chosen as the bifurcation parameters and those are varied in step for iterative calculation to find bifurcation points of periodic orbits of state variables.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.5
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• pp.107-120
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• 1999

Catalytic converters are the most fascinating and complicated chemical reactors. They are most often operated in the transient state with respect to composition, flow rate, temperature, etc. The mathermatical model developed in this work accounts for simultaneous heat and mass transfer, chemical reaction, and multi dimensional flow characteristics to analyze the light-off performance of monolithic catalytic converter with comparable mass flow rate. To validate the mathematical model, comparison between experimental and numerical results has been performed. The numerical results show a good agreement with experimental data. It is forund that inflow rate shows major effect on the characteristics of termal response of catalytic converter.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.3
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• pp.186-190
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• 2005

In this paper, the pipelined A/D converter with multi S/H stage structure is proposed for high resolution and high-speed data conversion rate. In order to improve a resolution and operational speed, the proposed structure increased the sampling time that is sampled input signal. In order to verify the operation characteristics, 20MS/s pipelined A/D converter is designed with two S/H stage. The simulation result shows that INL and DNL are $0.52LSB\~-0.63LSB$ and $0.53LSB\~-0.56LSB$, respectively. Also, the designed Analog-to-Digital converter has the SNR of 43dB and power consumption is 18.5mW.

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.273-276
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• 2003

In this paper, we designed and made up/down converter (UDC) for using W-CDMA digital pre-distortion system which is one of the efficiency enhancement techniques. UDC is required that frequency up(baseband to RF) and down(RF to baseband) of information signals. The focus of the design and PCB layout is to satisfy the linearity of the UDC. We tested that UDC was satisfied specification which is based on 3GPP base stations and repeaters. The ACLR results which are -51.84dBc(Up Converter) and -55.0dBc(Down Converter) at upper 5 MHz offset from center-frequency show that UDC satisfy the 3GPP specification with superior linearity data.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.12
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• pp.98-107
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• 1993

This paper describes a design of a multi-bit oversampling noise-shaping D/A converter which achieves a resolution of 12 bits using oversampling technique. In the architecture the essential block which determines the whole accuracy is the analog internal D/A converter, and the designed charge-integration internal D/A converter adopts a differential structure in order to minimize the reduction of the resolution due to process variation. As the proposed circuit is driven by signal clocks which contains the information of the data variation from the noise-shaping coder, it minimizes the disadvantage of a charge-integration circuit in the time axis. In order to verify the circuit, it was integrated with the active area of 950$\times$650${\mu}m^{2}$ in a double metal 1.5-$\mu$m CMOS process, and testified that it can achieve a S/N ratio of 75 dB and a S/(N+D) ratio of 60 dB for the signal bandwidth of 9.6 kHz by the measurement with a spectrum analyzer.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1196-1198
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• 2003

In this Paper, a PC-based virtual measuring program for efficiency measurement of DC-DC converter is developed. Furthermore, a newly developed highly accurate and reliable data acquisition system for DC-DC converter is presented. The virtual measuring system consists of two different types of monitoring and measuring system. Also, this paper give a full explanation for a LabVIEW realization of the measuring system for DC-DC converter.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.244-255
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• 2019

Interest in renewable energy has been increasing in recent years for many reasons, and there have been many studies on new types of wave energy converters and mechanisms for them. However, in this paper, motion characteristics of a wave energy converter with a wave activating body type is studied with an experiment. In order to conduct the experiment, a simple wave activating body type's wave energy converter is proposed. Experimental variations consist of connection type and location. The connection type controls the rotation motions of structures, and the connection location controls the distance between structures. The movement of floating structures, such as rotation, velocity, and acceleration, is measured with a potentiometer and a motion capture camera. Using the recorded data, the motion characteristics derived from the experimental variations are investigated.