• Journal of the Korean earth science society
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• v.37 no.5
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• pp.277-285
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• 2016

We introduce a depth scaling strategy to improve the accuracy of frequency-domain elastic full waveform inversion (FWI) using the new pseudo-Hessian matrix for seismic data without low-frequency components. The depth scaling strategy is based on the fact that the damping factor in the Levenberg-Marquardt method controls the energy concentration in the gradient. In other words, a large damping factor makes the Levenberg-Marquardt method similar to the steepest-descent method, by which shallow structures are mainly recovered. With a small damping factor, the Levenberg-Marquardt method becomes similar to the Gauss-Newton methods by which we can resolve deep structures as well as shallow structures. In our depth scaling strategy, a large damping factor is used in the early stage and then decreases automatically with the trend of error as the iteration goes on. With the depth scaling strategy, we can gradually move the parameter-searching region from shallow to deep parts. This flexible damping factor plays a role in retarding the model parameter update for shallow parts and mainly inverting deeper parts in the later stage of inversion. By doing so, we can improve deep parts in inversion results. The depth scaling strategy is applied to synthetic data without lowfrequency components for a modified version of the SEG/EAGE overthrust model. Numerical examples show that the flexible damping factor yields better results than the constant damping factor when reliable low-frequency components are missing.

• Journal of the Korean Society of Costume
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• v.15
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• pp.253-265
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• 1990

This article was written with two purposes in mind. The first purpose was to introduce clothing and textile community who may not be familiar with Multidimensional Scaling(MDS) with usefulness of the new technique in the area of fashion merchandising. The second purpose was to present the results of an empirical study on brand image utilizing MDS and its related technique as the main analysis tools. The main objective of the empirical study was to gain a better understanding of consumer's brand image by relating differences in perception and attributes of clothing in women's ready-to wear market. For this empirical study, the ten brands and the fifteen attributes of clothing were chosen. The questionnaire consisting of questions asking about the similarity and attributes of clothing between selected brands was administrated to 185 career women during summer in 1989. Data were analyzed cluster analysis, and KYST and PROFIT in MDS program. The results were as follows: 1. The similarities data for the ten selected brand by using KYST program of MDS drawed the perceptual map. The results of this perceptual map showed that the selected brand were grouped into three clusters. 2. In order to get a somewhat objective view of which attributes consumers are attributing to each brand, PROFIT program was used. As a result, it was revealed that assortment depth / width, price, youth-oriented style, possibility of various social activity were significant attributes in consumer's brand choice rather than physical attributes of clothing such as quality or durability. This may imply that consumer orientation in rapidly changing environments of women's apparel market was its basic idea, and the focus of all fashion merchandising activities was put on need's and the response of consumer group who are the object of the target. Implicating for future research as well as for strategy of brand positioning were also suggested.