• The Korean Journal of Applied Statistics
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• v.23 no.2
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• pp.285-293
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• 2010

The traditional methods for evaluating response surface designs are alphabetic optimality criteria. These single-number criteria such as D-, A-, G- and V-optimality do not completely reflect the prediction variance characteristics of the design in question. Alternatives to single-numbers summaries include graphical displays of the prediction variance across the design regions. We can suggest the animated quantile plots as the animation of the quantile plots and use these animated quantile plots for comparing and evaluating response surface designs.

• Journal of KSNVE
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• v.7 no.2
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• pp.247-254
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• 1997

In the case of a precision equipment, it requires a vibration free environment to provide its proper function. Especially, lithography and inspection devices, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved giga class semiconductor wafers. This high technology equipments require very strict environmental vibration standard in proportion to the accuracy of the manufacturing, inspecting devices. The vibration criteria are usually obtained either by the real vibration exciting test on the equipment or by the analytical calculation. This paper proposes a new method to solve this problem at a time. The permissible vibration level to a precision equipment can be easily obtained by analyzing a process of Frequency Response Function. This paper also demonstrates its effectiveness by applying the proposed method to finding the vibration criteria of a Computer Hard Disk Driver by Impact Test.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.5
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• pp.712-720
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• 2012

Recently, many problems related on shoreline response to spill oil were exposed again on a occasion of M/T Hebei spirit accident even though the weakness on the shoreline response system has been brought up since M/T Sea Prince oil spill accident. Therefore the establishment of shoreline response system that best suits our country is needed through considering the response system of well-developed country. The socioeconomic conflict between the persons concerned on the clean-up endpoints can be sharpened in Korea because the frequency of coastal use of our country is too high compared to other countries. Thus procedural justification, that is, how the clean-up endpoints be established is more important than what type of clean-up endpoints be used. In the present paper, we attempted to suggest a new manner on the decision making system for clean-up endpoints that best suits our country. The decision making system for clean-up endpoints need to be divided into two steps, that is, set-up step of clean-up endpoints criteria and decision step of clean-up endpoints. The decision making organization of local governments play a key role in case of set-up step of clean-up endpoints criteria, while the response command headquarters under Korean coast guard and decision making organization of local governments codecide whether the clean-up endpoints criteria is fits or not.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.250-255
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• 2017

When an earthquake occurs, it is necessary to evaluate the site-specific ground response while considering ground characteristics in seismic design. The design seismic force of Korean seismic design criteria is borrowed from the Uniform Building Code(UBC-1997). However, the criteria are based on the ground characteristics of the United States, which are different from the ground characteristics in Korea, and using them could cause over-or under-designing. Therefore, it is important to develop a proper design response spectrum for Korean ground characteristics. In this study, 158 ground sites in Korean urban areas were selected and compared to those in the western part of the United States, and their site-specific ground responses were analyzed. The classification standard in the seismic design criteria classifies the 158 sites into 37 sites, 107 sites, and 14 sites. Using 7 earthquake inputs, the criteria were compared for each group.The Korean design response spectrum underestimates the amplification of the short-period range and overestimates the amplification in the long-period range. There were large differences in the results of the and sites,which account for 77 percent of the 158 sites. Therefore, there is a need to modify the amplification factor in the Korean seismic criteria to properly reflect Korean ground characteristics.

• Communications for Statistical Applications and Methods
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• v.16 no.1
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• pp.195-208
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• 2009

A conventional single design optimality criterion has been used to select an efficient experimental design. But, since an experimental design is constructed with respect to an optimality criterion pre specified by investigators, an experimental design obtained from one optimality criterion which is superior to other designs may perform poorly when the design is evaluated by another optimality criterion. In other words, none of these is entirely satisfactory and even there is no guarantee that a design which is constructed from using a certain design optimality criterion is also optimal to the other design optimality criteria. Thus, it is necessary to develop certain special types of experimental designs that satisfy multiple design optimality criteria simultaneously because these multi-optimal designs (MODs) reflect the needs of the experimenters more adequately. In this article, we present a heuristic approach to construct second-order response surface designs which are more flexible and potentially very useful than the designs generated from a single design optimality criterion in many real experimental situations when several competing design optimality criteria are of interest. In this paper, over cuboidal design region for $3\;{\leq}\;k\;{\leq}\;5$ variables, we construct multi-optimal designs (MODs) that might moderately satisfy two famous alphabetic design optimality criteria, G- and IV-optimality criteria using a GA which considers a certain amount of randomness. The minimum, average and maximum scaled prediction variances for the generated response surface designs are provided. Based on the average and maximum scaled prediction variances for k = 3, 4 and 5 design variables, the MODs from a genetic algorithm (GA) have better statistical property than does the theoretically optimal designs and the MODs are more flexible and useful than single-criterion optimal designs.

• Earthquakes and Structures
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• v.3 no.3_4
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• pp.341-363
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• 2012

The spectral representation method is a quick and versatile tool for the generation of spatially variable, response-spectrum-compatible simulations to be used in the nonlinear seismic response evaluation of extended structures, such as bridges. However, just as recorded data, these simulated accelerations require processing, but, unlike recorded data, the reasons for their processing are purely numerical. Hence, the criteria for the processing of acceleration simulations need to be tied to the effect of processing on the structural response. This paper presents a framework for processing acceleration simulations that is based on seismological approaches for processing recorded data, but establishes the corner frequency of the high-pass filter by minimizing the effect of processing on the response of the structural system, for the response evaluation of which the ground motions were generated. The proposed two-step criterion selects the filter corner frequency by considering both the dynamic and the pseudo-static response of the systems. First, it ensures that the linear/nonlinear dynamic structural response induced by the processed simulations captures the characteristics of the system's dynamic response caused by the unprocessed simulations, the frequency content of which is fully compatible with the target response spectrum. Second, it examines the adequacy of the selected estimate for the filter corner frequency by evaluating the pseudo-static response of the system subjected to spatially variable excitations. It is noted that the first step of this two-fold criterion suffices for the establishment of the corner frequency for the processing of acceleration time series generated at a single ground-surface location to be used in the seismic response evaluation of, e.g. a building structure. Furthermore, the concept also applies for the processing of acceleration time series generated by means of any approach that does not provide physical considerations for the selection of the corner frequency of the high-pass filter.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.731-733
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• 1998

PID controllers are widely used in the process industries such as power plants and chemical plants. Several methods for determining PID controller parameters have been suggested to improve tuning results by various performance criteria during the past years. These methods may not produces satisfactory closed loop response by the characteristics of controlled processes. In this paper, using a model of gas turbine system obtained by operating data of Gunsan C/C, we examines the performance of PI controllers determined by various performance criteria and suggests which tuning methods can be optimally used in gas turbine control system of Gunsan C/C.

• Steel and Composite Structures
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• v.24 no.6
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• pp.643-658
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• 2017

High strength preloadable bolt assemblies are commonly adopted in beam-to-column bolted connections. Nowadays, two systems of high strength preloadable grade 10.9 bolt assembly are recommended in Europe for structural applications, namely HR and HV, which are characterized by different failure modes. Recently, experimental tests performed on HR and HV bolt assemblies highlighted that the type of bolt assembly may significantly influence the joint response. Therefore, the accuracy of numerical modelling of bolt assemblies is crucial to simulate effectively the non-linear behaviour of bolted joints with either failure mode 2 or mode 3 of the bolt rows. In light of these considerations, this present paper describes and discusses some modelling criteria for both HR and HV bolts to be implemented in 3D finite element models by finite element analysis and structural designers. The comparison between the calibrated models and experimental results shows the accuracy of the proposed assumptions in simulating all stages of assembly tensile response.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.6
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• pp.663-673
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• 2008

The purpose of this study is to analyze the appropriate evaluation method for the water supply and drain noise of bathroom in apartment and to propose some fundamental idea on its regulation. For this reason, it was studied the acoustical characteristics of water supply and drain noise as modifying the water supply pressure for the washbasins and toilet stools and suggested the optimum evaluation method through psychoacoustic test. As a result of investigation of the levels by evaluating the adjectives and noise sources with 7-step criteria corresponding to each level of plumbing noises and analysis of the correlation between physical evaluation values by comparing the criteria, dB(A), N, and NC, with subject's response, determination coefficient($R^2$) was shown to be relatively fair or higher ranged from 0.65 to 0.92. It is shown that 'Harsh', 'Nervous', 'Unpleasant', 'Distasteful', and 'Repellent' as a second factor are to be appropriate to evaluate plumbing noise. Above these results could be used in basic data establishing KS(Korean Standard) for evaluation and rating procedure and measures reducing these noise.

• Wind and Structures
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• v.8 no.4
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• pp.251-268
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• 2005

This paper describes the work of the International Association for Wind Engineering Working Group E -Dynamic Response, one of the International Codification Working Groups set up at the Tenth International Conference on Wind Engineering in Copenhagen. Comparisons of gust loading factors and wind-induced responses of major codes and standards are first reviewed, and recent new proposals on 3-D gust loading factor techniques are introduced. Then, the combined effects of along-wind, crosswind and torsional wind load components are discussed, as well as the dynamic characteristics of buildings. Finally, the mathematical forms of along-wind velocity spectra for along-wind response calculation and codification of acceleration criteria are discussed.