• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1235-1241
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• 2001

Pantograph design process must be considered in terms of stability of aerodynamics and reduction of aeroacoustics. Furthermore Pantograph needs to be insensible to severe circumstance condition like typhoon, tunnel, a change of season. In this paper, robust design of panhead sections is conducted based on the Taguchi's design of experiment method. In the aeroacoustic noise analysis, an acoustic analogy using the Ffowcs Williams and Hawkings (FW-H) equation is used to calculate the flow induced sound pressure level. From the near-field CFD analysis data, the far-field noise is predicted at the positions of 25m away from panhead contact strips. Based on aerodynamic (CFD) and aeroacoustic (FW-H) analysis data, the optimal sizing and positioning ofpanhead elements are determined using robust design optimization method. Design parameters such as thickness, length and radius are controllable factors, while outdoor air temperature and atmospheric pressure are considered as uncontrollable factors in the context of Taguchi's approach. A number of CFD simulation and aeroacoustic analysis are performed based on orthogonal arrays. Using a parameter design procedure associated with signal-to-noise (SIN) ratio and sensitivity analysis, an optimal level of design parameters are extracted to minimize the disconnection ratio between contact strips and catenary system, and reduce the far-field aeroacoustic noise.

• Journal of the Earthquake Engineering Society of Korea
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• v.26 no.3
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• pp.127-136
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• 2022

Recently, an unprecedented emerging infectious disease has rapidly spread, causing a global shortage of wards. Although various temporary beds have appeared, the supply of wards specializing in infectious diseases is required. Negative pressure isolation wards should maintain their function even after an earthquake. However, the current seismic design standards do not guarantee the negative pressure isolation wards' operational (OP) performance level. For this reason, some are not included in the design target even though they are non-structural elements that require seismic design. Also, the details of non-structural elements are usually determined during the construction phase. It is often necessary to complete the stability review and reinforcement design for non-structural elements within a short period. Against this background, enhanced performance objectives were set to guarantee the OP non-structural performance level, and a computerized tool was developed to quickly perform the seismic design of non-structural elements in the negative pressure isolation wards. This study created a spreadsheet-based computer tool that reflects the components, installation spacing, and design procedures of non-structural elements. Seismic performance review and design of the example non-structural elements were conducted using the computerized tool. The strength of some components was not sufficient, and it was reinforced. As a result, the time and effort required for strength evaluation, displacement evaluation, and reinforcement design were reduced through computerized tools.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1261-1264
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• 1996

This paper presents the design of a neural network based PWM technique for a three level inverter of electric trains. A three-level inverter has several advantages compared with a two-level inverter in this application. In viewpoint of correcting unbalance of DC-link voltage, a novel method is developed and verified in computer simulation.

• Journal of the Korea Institute of Building Construction
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• v.12 no.6
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• pp.674-681
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• 2012

With the rise in the functions required in modern building structures, the role of the building equipment that maintains the functions of a building has been emphasized and increased. Effective management in this area is only possible when the construction manager (CMr) is qualified and has the knowledge of building equipment that is needed. Therefore, in this study, a questionnaire survey was carried out on equipment engineers and CMrs, in order to determine the level of building equipment knowledge required, and to identify the perception level of CMrs about the building equipment in the construction project at the project design stage. The results of this study revealed that the CMrs surveyed had a lower level of knowledge on the building equipment than the level that was desired by the equipment engineers. This indicates that CMrs currently have a weak capacity for the management of building equipment. It is thus necessary for CMrs to undergo systematic training in order learn more about building equipment and thus be able to manage construction projects more efficiently.

• Journal of the Korean Geotechnical Society
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• v.21 no.7
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• pp.63-72
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• 2005

Grounwater level applied on dredged and reclaimed clay layer was assumed to be the same value under design criterion as field test one, but actually differences are found through the monitoring test. In this study, a case study of measuring residual groundwater level is performed in ground improvement construction of Gwangyang container terminal and hinterland. With priority given to residual groundwater level measured during construction and management period of 9 years, it is investigated that residual groundwater level (R. GWL) could be applied reasonably to the design, construction, and use stages of the container harbor and land development.

• Advances in Computational Design
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• v.3 no.4
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• pp.339-366
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• 2018

Parametric design systems serve as powerful assistive tools in the design process by providing a flexible approach for the generation of a vast number of design alternatives. However, contemporary parametric design systems focus primarily on low-level engineering and structural forms, without an explicit means to also take into account high-level, cognitively motivated people-centred design goals. We present a precedent-based parametric design method that integrates people-centred design "precedents" rooted in empirical evidence directly within state of the art parametric design systems. As a use-case, we illustrate the general method in the context of an empirical study focusing on the multi-modal analysis of wayfinding behaviour in two large-scale healthcare environments. With this use-case, we demonstrate the manner in which: (1). a range of empirically established design precedents -e.g., pertaining to visibility and navigation- may be articulated as design constraints to be embedded directly within state of the art parametric design tools (e.g., Grasshopper); and (2). embedded design precedents lead to the (parametric) generation of a number of morphologies that satisfy people-centred design criteria (in this case, pertaining to wayfinding). Our research presents an exemplar for the integration of cognitively motivated design goals with parametric design-space exploration methods. We posit that this opens-up a range of technological challenges for the engineering and development of next-generation computer aided architecture design systems.

• Explosives and Blasting
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• v.30 no.2
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• pp.86-97
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• 2012

Ground vibration induced by a bench blasting in the construction site should cause the damage to the structure and indirect damage to a human body, and the vibration level is most practical descriptor for regulating the damage to human body and peak particle velocity is the descriptor for direct damage assesment of the structure. Meantime, the vibration level has not been considered for the blasting design but this study is the case that apply not only peak particle velocity but also vibration level on the blasting design. Also, we strongly believe that this study will be helpful for the management in the blasting site which some civil appeal is concerned. Total 232 measurements of both ppv and vibration level was used to estimate the scale distance. When the regulating threshold was ppv 0.3 cm/s and vibration level 75 decibel, the charge per delay to be estimated with vibration level could be recommended by 1.2~1.4 times than it of ppv. So, it is proven that considering vibration level on the blasting design is reasonable for not only prevention of the civil appeals but also effective blasting. Again, the blasting design which follows the law, "Noise and Vibration Control Act" can actually serve good condition to carry much more economical and effective blasting. The instruments used for this study are the SV-1 model, as first instrument in korea which can measure vibration velocity and vibration level at the same time.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.963-966
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• 2001

The wideband DS-CDMA (W-CDMA) system is one of the candidates for the next generation mobile communication system known as IMT-2000. The important concept of W-CDMA is the introduction of intercell asynchronous operation. In this paper, we design and analyze the system level simulator for the International Mobile Tele communication - 2000 (IMT-2000) 3-rd generation partnership project (3GPP) system. We confirm how the simulator works by BER over different Eb/NO. This study will be expected to use as reference data in the development of asynchronous IMT-2000. In this paper, we analyze a physical layer of W-CDMA system and design a transmitter and receiver by using ADS (Advanced Design System). Also, we simulated a link level performance in Rayleigh fading channel environment. This study will be useful in the analysis and design of W-CDMA system.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.240-245
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• 2001

In axiomatic approach for design evaluation, even if a mutual relation don't appear physical mapping of high level, it can appear in process mapping of low level through coupled PVs(Process Variables), but we must solve it for correct design evaluation. This paper handle a method for solving of coupled PVs by using axiomatic approach and CBR(Case-Based Reasoning). The methodology of proposal took still more shape through the instance of MCPs(Microcellular Plastics).

• The KSFM Journal of Fluid Machinery
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• v.9 no.2 s.35
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• pp.13-18
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• 2006

This paper was studied to design Process considered flexibility and reliability of suction and discharge valves. Flexibility and reliability of valves are main important factors in compressor valves design. And they are incompatible with efficiency of compressor. In this study, we have performed the optimal design of CO2 compressor valves to consider these factors. At first, we analyzed performance simulation of compressor to obtain optimal flexibility level of valves. From this simulation, we could get some important data at valve design like the optimal natural frequency and the height of retainer. After that we studied to reliability of valves corresponding to optimal flexibility level by finite element method. For each case bending stress and natural frequency were obtained by it. Also we investigated the fatigue stability to obtain optimal valve shape that ensured to reliability.