• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.06a
• /
• pp.1627-1632
• /
• 2000

Recently, piezoelectric materials have attracted considerable attention because of its self-sensing and actuating properties. To model smart structures, numerical modeling of structures with piezoelectric devices is essential. As many factors affect the performance of smart structures, optimization of these parameters is necessary. In this paper, the shape design sensitivity analysis of the 3D piezoelectric and structural elements is developed and shape optimization is performed. For the evaluation of the sensitivity, the finite element method is used. For the shape sensitivity, the domain velocity field is calculated. An acoustic cavity model is presented as a numerical example to study the feasibility of the formulation. The continuum sensitivity is compared with the results of the finite difference method by ANSYS. And the sequential linear programming (SLP) algorithm is used as the optimization algorithm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.3
• /
• pp.218-222
• /
• 2007

In this study, Acoustic emission(AE) sensors were fabricated using lead-free piezoelectric ceramics for prohibiting environmental pollution. Structure of AE sensors were designed as Langvin type air backing form. Here, the piezoelectic element was used as PZT(EC-65)(AE1) and NKN(AE2), respectively. The measured resonant frequency, the maximum sensitivity frequency and sensitivity of AE sensors were as follows ; 143 kHz, 29.4 kHz and 69.3 dB in AE1 and 179 kHz, 29.4 kHz and 66.3dB in AE2, respectively.

• Journal of the Korea Furniture Society
• /
• v.28 no.4
• /
• pp.332-339
• /
• 2017

Today, our indoor space requires a user-centered considering design that satisfies even human sensitivity. The word 'sensitivity' is being frequently used in the design market recently and this means that consumers are becoming more sensitive. For this reason, the characteristics of Toyo Ito's architecture, which are innocent due to its natural structure and materials, are suggested as a sensitive lighting stand design which can relieve users' stress from daily life and bring a psychological stability. As such, sensitivity lighting can create a lighting environment that considers consumers in various spaces along with the development of new scientific technologies and develop in a new direction of aesthetical beauty and eco-friendly area. In this study, a natural and sensitive lighting stand is suggested where a variety of digital art techniques of LED are applied based on formative characteristics of relationship, one of Toyo Ito's architectural concept factors. Such sensitivity lighting designs can not only realize a type-free design but also suggest a creation of the atmosphere which is close to nature.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.19 no.1 s.71
• /
• pp.63-71
• /
• 2006

This study presents the effective stiffness-based optimal technique to control Quantitatively lateral drift for shear wall-frame structure system using sensitivity analysis. To this end, the element stiffness matrices are constituted to solve the compatibility problem of displacement degree of freedom between the frame and shear wall. Also, lateral drift constraint to introduce the approximation concept that can preserve the generality of the mathematical programming and can effectively solve the large scaled problems is established. And, the section property relationships for shear wall and frame members are considered in order to reduce the number of design variables and differentiate easily the stiffness matrices. Specifically, constant-shape assumption which is uniformly varying in size during optimal process is applied in frame structure. The thickness or length of shear wall can be changed depending on user's intent. Two types of 20 story shear wall-frame structure system are presented to illustrate the features of the stiffness-based optimal design technique.

• Journal of Ocean Engineering and Technology
• /
• v.11 no.2
• /
• pp.11-17
• /
• 1997

Simple and efficient way of nonlinear analysis considering elasto-plastic large deformation is introduced to calculate the strength of ring-stiffened cylinears subject to combined load of axial compression and lateral pressure. Parametric study gives various collapse modes according to the combination ratio of axial compression and lateral pressure, interaction between axial compression and lateral pressure and imperfection sensitivity of ultimate strength.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.760-763
• /
• 2003

This study proposed the analysis of damage defection due to the change of the stiffness of structure by using the original and modified dynamic characteristics. The method is applied to examples of a cantilever and 3 degree of freedom by modifying the stiffness. The predicted damage detections are in good agreement with these from the structural reanalysis using the modified stiffness.

• Structural Engineering and Mechanics
• /
• v.59 no.3
• /
• pp.559-577
• /
• 2016

There are many theoretical analyses and experimental studies of the hydrodynamics for the tension leg platform (TLP) of a floating wind turbine. However, there has been little research on the arrangement of the TLP's internal structure. In this study, a TLP model and a 5-MW wind turbine model as proposed by the Minstitute of Technology and the National Renewable Energy Laboratory have been adopted, respectively, to comprehensively analyze wind effects and wave and current combinations. The external additional coupling loads on the TLP and the effects of the loads on variables of the internal structure have been calculated. The study investigates preliminary layout parameters-namely, the thickness of the tension leg body, the contact mode of the top tower on the tension leg, the internal stiffening arrangement, and the formation of the spoke structure-and conducts sensitivity analyses of the TLP internal structure. Stress is found to be at a maximum at the top of the tension leg structure and the maximum stress has low sensitivity to the load application point. Different methods of reducing maximum stress have been researched and analyzed, and the effectiveness of these methods is analyzed. Filling of the spoke structure with concrete is discussed. Since the TLP structure for offshore wind power is still under early exploration, arrangements and the configuration of the internal structure, exploration and improvements are ongoing. With regard to its research and analysis process, this paper aims to guide future applications of tension leg structures for floating wind turbine.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.22 no.6
• /
• pp.1403-1409
• /
• 2008

The purpose of this study is to develop the systematic process on the discrimination of Sasang constitution with the pulse diagnosis apparatus. The pulse waves were acquired at the right and the left Guan point with 1420 people who were apparently healthy. In order to minimize the effect of aging on the shape of pulse wave, the age groups of 30s, 40s, and 50s were used. Taeum group was the best to classify, Soyang group was the worst. With the same group size, the sensitivity of Soyang group was increased. Input variables were selected with the consideration of the floating-sink ratio, tests of equality of group means, multiple comparison, multicollinearity, and structure matrix. To increase the sensitivity of Soyang, the variables which could tell the difference between Soyang and Soeum were selected.

• Proceedings of the KSR Conference
• /
• 2000.11a
• /
• pp.48-59
• /
• 2000

In tins paper, we outlines the pricing concept that developed over the years, and illustrates how these rules apply in practice using railway fare, price discrimination in railway travel. We review tile prospective solution of rail fare system reflecting the customer need on the decision making and consider fare design structure. Specifically, we focus on the price range using the PSM(price sensitivity measure). And set up the framework for fare structure design.

• Science of Emotion and Sensibility
• /
• v.10 no.3
• /
• pp.393-402
• /
• 2007

The purpose of this study is to provide the design direction based on consumer sensitivity through the structure between product design preferences - sensitivity image - design elements. For the purpose, we selected men's shaver products for this study subject and collected 164 shavers' pictures released between 2001-2007 years. Then, we carried out a pilot test for collection of sensitivity images about shavers, made a survey using semantic differential method and analyzed the survey. According the result, consumers preferred the sensitivity images "luxury, attractive, stable", design elements satisfied the preference images were "form of body is not a circular arcs or a polygon, material is steel, button is push style, and a color of body is not brown." This study can provide a base of the causal relationship between design preferences - sensitivity image - design elements and a design process to predict consumer sensitivity-oriented design.