• Advances in nano research
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• v.9 no.3
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• pp.133-145
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• 2020

In this study, nonlinear vibrations and dynamic instabilities of a smart embedded micro shell conveying varied fluid flow and subjected to the combined electro-thermo-mechanical loadings are investigated. With the aim of designing new hydraulic sensors and actuators, the piezoelectric materials are employed for the body and the effects of applying electric field on the stability of the system as well as the induced voltage due to the dynamic behavior of the system are studied. The nonlocal piezoelasticity theory and the nonlinear cylindrical shell model in conjunction with the energy approach are utilized to mathematically modeling of the structure. The fluid flow is assumed to be isentropic, incompressible and fully develop, and for more generality of the problem both steady and time dependent flow regimes are considered. The mathematical modeling of fluid flow is also carried out based on a scalar potential function, time mean Navier-Stokes equations and the theory of slip boundary condition. Employing the modified Lagrange equations for open systems, the nonlinear coupled governing equations of motion are achieved and solved via the state space problem; forth order numerical integration and Bolotin's method. In the numerical results, a comprehensive discussion is made on the dynamical instabilities of the system (such as divergence, flutter and parametric resonance). We found that applying positive electric potential field will improve the stability of the system as an actuator or vibration amplitude controller in the micro electro mechanical systems.

• The Journal of Information Systems
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• v.20 no.1
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• pp.107-126
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• 2011

Model-based decision support system (DSS) has acted as a crucial role in strengthening the business competitiveness by providing a way of modeling and solving real-world decision problems in a quantitative and scientific manner. It is even more important for trading OTC derivatives, which requires extensive financial-engineering expertise while actively reacting to the continuously changing financial market. This paper proposes a flexible model-based DSS architecture that can support user-friendly interface for executing and analyzing the models and can adapt to the changes of financial market seamlessly. For user-friendliness, we implement the user-interfaces (UIs) using Microsoft Excel, a very widely used spreadsheet program for its great generality and extensibility. Users can utilize the analysis results of DSS or reprocess them for their special needs through the UIs in the form of familiar spreadsheets easily. For adaptiveness to the markets, the proposed architecture is constructed based on the object-oriented concepts, which enables such changes as release of a new financial product can be updated into the system without any delay at the lowest cost. We investigate the practical benefits and limitations of the proposed architecture by a case study on the construction of Model-based Trading Support System (MTSS), performed by a commercial bank in Korea.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.1
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• pp.17-22
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• 2011

Based on the form of the Tsai-Hill criterion, a new failure criterion for anisotropic material subjected to combined stress is developed and demonstrated. It is capable of accurately calculating the strength of anisotropic materials. The generality and accuracy of the present failure criterion are illustrated by examination through the use of Kraft paperboards under various loading conditions. Compared to the Tsai-Hill theory, which is much too conservative at high levels of shear stress, the present criterion has a good agreement with the experimental data. It also has the ability to calculate the strength more simply, compared to the Tan-Cheng theory.

• Korean Journal of Computational Design and Engineering
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• v.16 no.6
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• pp.458-466
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• 2011

The morphology of a bone is closely associated with its biomechanical response. Thus, much research has been focused on analyzing the effects of variation of bone morphology with subject-specific models. Subject-specific models, which are generally achieved from 3D imaging devices like CT and MRI, incorporate more of the detailed information that makes a model unique. Hence, it may predict individual responses more accurately. Despite these powerful characteristics, specific models are not easily parameterized to the extent possible with statistical models because of their morphologic complexities. Thus, it is still proven challenging to analyze morphologic variations of subject-specific models across changes due to aging or disease. The aim of this article is to propose a generic and robust parametric morphing method for a subject-specific bone structure. We demonstrate this by using the proposed method on a model of a human proximal femur. Automatic segmentation algorithms are also presented to parameterize the specific model efficiently. A total of 48 femur models were evaluated for defining morphing vector fields. Also, several anatomical and mechanical functions of femur were considered as morphing constraints, and the NURBS interpolating technique was applied in the method to guarantee the generality of our morphed results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.3
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• pp.419-426
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• 1986

In an attempt to develop a method for the design of the aerial rope way, the traditional theories of rope way were examined and compared. The resulting formulas of the traditional and approximate parabolic curve theory were summarized and those of the catenary curve theory as an exact ones were summarized and newly developed when necessary. In particular, it was found that the resulting formulas from both of these theories can fully be expressed with only three dimensionless parameters $U^{*}$, $V^{*}$, and $W^{*}$, improving compactness and generality of these formulas. Comparision of the theories were done through error analysis, and it was shown that the error of the approximate parabolic curve is of order $U^{*2}$ and $V^{*}$. From this, it was concluded that the traditional parabolic curve theory has its limitation when the rope way becomes larger or steeper, leading to the necessity of the use of catenary curve theory.ve theory.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.10 no.2
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• pp.53-66
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• 2006

Recent technique has shown high interest in 3D stereoscopic image, one out of high immersion appearance techniques. Unlike general 2D image, 3D stereoscopic image is generated by 3D geometric information. Therefore, the lack of 3D geometric information sometimes imposes restrictions or makes editing more tedious. We propose a new unsupervised technique aimed to generate stereoscopic image which is estimated by depth-map information using image-based modeling from a single input image. The proposed system is implemented as the Adobe Photoshop(R) plug-in for considering generality and expandability, and also supports a preview function of interactive 3D stereoscopic image to determine stereoscopic view of high quality.

• Journal of Computing Science and Engineering
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• v.3 no.2
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• pp.127-141
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• 2009

In this paper, we describe our vision of a "Just-in-time" initiative to solve the Data Interoperability Problem (a.k.a. INTEROP.) We provide an architectural overview of our initiative which draws upon existing technologies to develop an immersive and collaborative approach which aims at empowering data stakeholders (e.g., data producers and data consumers) with integrated tools to interact and collaborate with each other while directly manipulating visual representations of their data in an immersive environment (e.g., implemented via Second Life.) The semantics of these visual representations and the operations associated with the data are supported by ontologies defined using the Common Logic Framework (CL). Data operations gestured by the stakeholders, through their avatars, are translated to a variety of generated resources such as multi-language source code, visualizations, web pages, and web services. The generality of the approach is supported by a plug-in architecture which allows expert users to customize tasks such as data admission, data manipulation in the immersive world, and automatic generation of resources. This approach is designed with a mindset aimed at enabling stakeholders from diverse domains to exchange data and generate new knowledge.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.10
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• pp.150-158
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• 2003

In the beam pattern synthesis problem using line source, the relationship between source distribution function and beam pattern may be represented by Fourier transform pair. In this paper, a general method to synthesize the line source distribution for a desired lobe-like beam pattern is presented by developing the nonlinear inversion method based on an iterative sampling technique. This method can be applied to the synthesis of continuously distributed dielectric constants satisfying the desired inverse scattering coefficient patterns when illuminating by TE-polarized and TM-polarized plane waves to arbitrary dielectric material. Furthermore this method can also be applied to the synthesis of transmission line with arbitrary reflection coefficient patterns. Some bandstop spatial filter and dispersive transmission line filter are illustrated for generality.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.7
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• pp.323-327
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• 2005

This paper presents an operator training simulator for power system restoration against massive black-out. The system is designed especially focused on the generality and convenient setting up for initial condition of simulation. The former is accomplished by using power flow calculation methodology, and PSS/E data is used to define the initial situation. The proposed simulator consists of three major components - the power flow(PF) module, data conversion(COW) module and GU subsystem. PF module calculates power flow, and then checks overvoltage of buses and overflow of lines. COW module composes an Y-Bus array and a data base at each restoration action. The initial Y-Bus array is constructed from PSS/E data. The user friendly GUI subsystem is developed including graphic editor and built-in operation manual. As a result, the maximum processing time for one step operation is 15 seconds, which is adequate for training purpose. Comparison with PSS/E simulation proves the accuracy and reliability of the training system.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.534-540
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• 1993

In this paper, we present an iterative learning method of compensating for position sensor error. The previously known compensation algrithms need a special perfect position sensor or a priori information about error sources, while ours does not. To our best knowledge, any iterative learning approach has not been taken for sensor error compensation. Furthermore, our iterative learning algorithm does not have the drawbacks of the existing iterative learning control theories. To be more specific, our algorithm learns a uncertain function inself rather than its special time-trajectory and does not request the derivatives of measurement signals. Moreover, it does not require the learning system to start with the same initial condition for all iterations. To illuminate the generality and practical use of our algorithm, we give the rigorous proof for its convergence and some experimental results.