• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1829-1831
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• 2001

A novel multi-section power divider configuration is proposed to obtain wide-band frequency performance up to microwave frequency region. Design procedures for the proposed microwave broadband power divider are composed of a planar multi-section three-ports hybrid and a waveguide transformer design procedures. The multi-section power divider is based on design theory of the optimum quarter-wave transformer. Furthermore, in order to obtain the broadband isolation performance between the two adjacent output ports, the odd mode equivalent circuit should be matched by using the lossy element such as resistor. The derived design formula for calculating these odd mode matching elements is based on the singly terminated filter design theory. The waveguide transformer section is designed to suppress the propagation of the higher order modes such as waveguide modes due to employing the metallic electric wall. Simulation and experiment show excellent performance of multi section power divider.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.1
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• pp.168-178
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• 2002

The purpose of this study is to develop an optimal performance design ova concrete median barrier using the design of experiment and crash simulation which is done by Pam-Crash, one of the commercial crash simulation software. A formula of characteristic value was suggested to obtain an optimal performance design considering all of von Mises stress, volume and acceleration at center of gravity of a heavy truck. An optimal design of a concrete median barrier was obtained by the analysis of variance based on design of experiment and crash simulation. A crash simulation with the optimal design was accomplished in order to verify the suitability of the suggested formula and the proper application of the design of experiment. The obtained optimal design was satisfied for a domestic design regulation of a concrete median barrier.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.5
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• pp.299-309
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• 2018

Now that problems with force-based seismic design have been clearly identified, design is inclined toward displacement-based methods. One such widely used method is Direct-Displacement-Based Design (DDBD). Yet, one of the shortcomings of DDBD is considering higher-mode amplification of story shear, moments, and displacements using equations obtained from limited parametric studies of regular planar frames. In this paper, a different approach to account for higher-mode effects is proposed. This approach determines the lateral secant stiffness of the building frames that fulfill the allowable inter-story drift without exceeding the desired story displacements. Using the stiffness, an elastic response spectrum analysis is carried out to determine elastic higher-mode force effects. These force effects are then combined with DDBD-obtained first-mode force effects using the appropriate modal superposition method so that design can be performed. The proposed design procedure is verified using Nonlinear Time History Analysis (NTHA) of twelve planar frames in four categories accounting for mass and stiffness irregularity along the height. In general, the NTHA response outputs compared well with the allowable limits of the performance objective. Thus, it fulfills the aim of minimizing the use of NTHA for planar frame buildings, thereby saving computational resources and effort.

• 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 SAREK Conference
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• 2009.06a
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• pp.1412-1417
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• 2009

BIM(Building Information Modeling) is considered a new paradigm and a powerful method in building design, construction and maintenance. However, it is still hard to implement environmental performance analysis using BIM in design stages. This study aims to reveal practical problems and evaluate interoperability between building design information and performance analysis with case studies. Three case studies are performed using two environmental analysis programs (IES/VE, EnergyPlus) and BIM-based architectural design programs (Revit, GoogleSketchUp) in this paper.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.114-119
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• 2004

For passenger vessels, twin shaft types in propulsion system is generally adopted to provide a high-speed performance in low draught due to restricted operating condition in harbors or water channels. Struts of twin open shaft type support the shafts, bearings, and propellers. Therefore, strut design is needed to consider not only hydrodynamic performance but also structural and noise/vibration performance, In this paper, considerations in strut design at the initial design stage have been discussed based on existing references, numerical calculations, and their comparisons. Also, the strut design of a RoPax ferry has been carried out at the initial design stage, for an example.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.824-836
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• 2008

Relaxed static stability(RSS) concept has been applied to improve aerodynamic performance of modern version supersonic jet fighter aircraft. Therefore, flight control systems are necessary to stabilize an unstable aircraft, and provides adequate handling qualities and achieve performance enhancements. Standard FCSDVP (Flight Control System Design and Verification Process) is provided to reduce development period of the flight control system. In addition, if this process is employed in developing flight control system, it reduces the trial and error for development and verification of flight control system. This paper addresses the flight control system design and verification process for the RSS aircraft utilizing design goal based on military specifications, linear and nonlinear system design and verification based on universal software, handling quality test based on HILS(Hardware In-the-Loop Simulator) environment, and ground and flight test results to verify aircraft dynamic flight responses.

• Journal of Ocean Engineering and Technology
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• v.24 no.4
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• pp.66-71
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• 2010

Numerical prediction of propeller performance plays an important role in a marine propeller design process. Program developers are consistently trying to improve diminish predicted errors, and program users need to keep up with the latest ones with minimum expenditure of time and money. We have developed an internet based design system in which clients can design propellers with remote access. In this paper, optimized Internet based Propeller Design and Analysis System (iProDAS) for transferences of the massive data is presented, and a sample design using iProDAS is examined.

• Steel and Composite Structures
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• v.42 no.1
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• pp.59-74
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• 2022

This study introduces a general reliability-based, performance-based design framework to design frames regarding their uncertainties and user-defined design goals. The Iterative-R method extracted from the main framework can designate a proper R (i.e., response modification factor) satisfying the design goal regarding target reliability index and pre-defined probability of collapse. The proposed methodology is based on FEMA P-695 and can be used for all systems that FEMA P-695 applies. To exemplify the method, multiple three-dimensional, four-story steel special moment-resisting frames are considered. Closed-form relationships are fitted between frames' responses and the modeling parameters. Those fits are used to construct limit state functions to apply reliability analysis methods for design safety assessment and the selection of proper R. The frameworks' unique feature is to consider arbitrarily defined probability density functions of frames' modeling parameters with an insignificant analysis burden. This characteristic enables the alteration in those parameters' distributions to meet the design goal. Furthermore, with sensitivity analysis, the most impactful parameters are identifiable for possible improvements to meet the design goal. In the studied examples, it is revealed that a proper R for frames with different levels of uncertainties could be significantly different from suggested values in design codes, alarming the importance of considering the stochastic behavior of elements' nonlinear behavior.

• Journal of the Korea Safety Management & Science
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• v.23 no.1
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• pp.57-64
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• 2021

Recently, advanced countries assessment the risk of fire to prevent large-scale damage to high-rise buildings, In addition, performance-Based design, which is a fire risk assessment, is being conducted in Korea to prevent massive damage to high-rise buildings. However, unlike advanced countries, fire risk assessment in Korea is subject to fire risk assessment only for objects subject to consent from fire-fighting facilities such as building permits, When building engineers and fire-fighting engineers assessment the risk of fire, It has always been discussed because the results vary depending on which part of the evaluation is focused between economic feasibility and safety. Therefore, in this study, we would like to propose a fire risk assessment process suitable for domestic conditions by comparing the process of performance-based design, which is a domestic fire risk assessment, and the process of Iso/TC 16732 which is an overseas fire risk assessment.