• Smart Structures and Systems
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• v.15 no.4
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• pp.1139-1158
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• 2015

This paper proposes an efficient system identification method for modeling nonlinear behavior of civil structures. This method is developed by integrating three different methodologies: principal component analysis (PCA), artificial neural networks, and fuzzy logic theory, hence named PANFIS (PCA-based adaptive neuro-fuzzy inference system). To evaluate this model, a 3-story building equipped with a magnetorheological (MR) damper subjected to a variety of earthquakes is investigated. To train the input-output function of the PANFIS model, an artificial earthquake is generated that contains a variety of characteristics of recorded earthquakes. The trained model is also validated using the1940 El-Centro, Kobe, Northridge, and Hachinohe earthquakes. The adaptive neuro-fuzzy inference system (ANFIS) is used as a baseline. It is demonstrated from the training and validation processes that the proposed PANFIS model is effective in modeling complex behavior of the smart building. It is also shown that the proposed PANFIS produces similar performance with the benchmark ANFIS model with significant reduction of computational loads.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.7-14
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• 2000

Nowadays, the viscous damper using high viscosity oil was much to be used for engine shafting system to reduce the excessive additional stress by torsional vibration. In general, it was assumed that the viscous damper could be modelled having only damping coefficient, that is to say, whose stiffness be ignored. But it is found that there exists a jump phenomenon, as a kind of non-linear vibration, in the actual engine shafting system with a damper of high viscosity. Therefore the damper ring and the casing are modelled as two mass elastic system with a complex viscosity. Also, to analyze a non-linear phenomenon, it is assumed that the viscous damper has a linear stiffness coefficient in proportion to the angular amplitude and a non-linear stiffness coefficient in proportion to cube of the angular amplitude. For the analysis, Quasi-Newton method with BFGS(Broyden-Fletcher-Goldfarb-Shanno) formula is used. Both calculated and measured values are provided in this paper which confirm the possibility of applying non-linear theory to engine shafting system with viscous damper.

• Earthquakes and Structures
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• v.10 no.6
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• pp.1253-1272
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• 2016

For a nonlinear control system, there are many uncertainties, such as the structural model, controlled parameters and external loads. Although the significant progress has been achieved on the robust control of nonlinear systems through some researches on this issue, there are still some limitations, for instance, the complicated solving process, weak conservatism of system, involuted structures and high order of controllers. In this study, the computational structural mechanics and optimal control theory are adopted to address above problems. The induced norm is the eigenvalue problem in structural mechanics, i.e., the elastic stable Euler critical force or eigenfrequency of structural system. The segment mixed energy is introduced with a precise integration and an extended Wittrick-Williams (W-W) induced norm calculation method. This is then incorporated in the market-based control (MBC) theory and combined with the force analogy method (FAM) to solve the MBC robust strategy (R-MBC) of nonlinear systems. Finally, a single-degree-of-freedom (SDOF) system and a 9-stories steel frame structure are analyzed. The results are compared with those calculated by the $H{\infty}$-robust (R-$H{\infty}$) algorithm, and show the induced norm leads to the infinite control output as soon as it reaches the critical value. The R-MBC strategy has a better control effect than the R-$H{\infty}$ algorithm and has the advantage of strong strain capacity and short online computation time. Thus, it can be applied to large complex structures.

• Management Science and Financial Engineering
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• v.8 no.1
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• pp.21-38
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• 2002

Rapid advances in information technology(IT) and telecommunication systems impact the number and quality of decision-making in organizations. Specifically, middle mangers must posses or develop the creativity necessary for survival in a constantly changing and volatile business environment. While tradition and conventional wisdom tell us that a middle managers role centers on control and monitoring, todays competitive arena has spun out a new managerial requirement developing and maintaining an innovative attitude. Problematically, most previous research has focused on the issue of changing decision authority (i. e. centralization/decentralization). Moreover, much previous research has also largely ignored environmental changes exposing new roles that middle managers have assumed. This study explores the means of identifying middle managerial roles, managerial possibilities involving the growing popularity of open systems through electronic brainstorming, and an adaptation and development of Diffusion Theory and attempt to counter criticism leveled at the theory's inability to provide an adequate explanation for diffusion of complex organizational technology. This paper develops three ideas: 1) Introducing the 'Chasing Curve' as a theoretical background. 2) Suggesting a new methodology using electronic brainstorming for analyzing the gap between Knowing (the perceived importance of middle managers' roles) and Doing (the degree of current status of middle managers' roles), which we term the 'Spiral Gap Analysis Model'. 3) Identifying a feedback system for minimizing the Knowing - Doing gap, aimed at development of IT strategic priority decision support, which we call this the 'Star Process'.

• Journal of Physiology & Pathology in Korean Medicine
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• v.33 no.6
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• pp.303-310
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• 2019

In order to search for the causes of having difficulty with the scientification task of the Korean medicine, the definition and conception of science were reviewed first and then formalization of reasoning scheme and a practical method of scientification were proposed. Science in its definition is meant by foundation of method and system for production of scientific knowledge not by knowledge of science itself. The formation of science is composed of complex processes including not only scientific knowledge but also politicosocial output containing activity of scientist society, spreading of social value and intercommunication. The production of scientific knowledge of Korean medicine is begun from logicality of the differential diagnosis and treatment theory through abductive verification of analogical inference by yinyang and 5 phase theory. For the commensurability between the various heterogenic theories within Korean medicine, the scientific activity of collecting, compiling, analyzing, distributing, and discussing the significant knowledge gained through abductive verification in the experiment and clinical process should be formed broadly. Based on these knowledge database, organization of scientist society with Korean medicine, life science, medical engineering, social expansion and generalization of pattern conception, and then social propagation and contribution for national health should be driven forward.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.720-723
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• 2005

Ship motion is a complex controlled process with several hydrodynamic parameters that vary in wide ranges with respect to ship load condition, speed and surrounding conditions (such as wind, current, tide, etc.). Therefore, to effectively control ships in a designed track is always an important task for ship masters. This paper presents an effective adaptive autopilot ships that ensure the optimal accuracy, economy and stability characteristics. The PID control methodology is modified and parameters of a PID controller is designed to satisfy conditions for an optimal objective function that comprised by heading error, resistance and drift during changing course, and loss of surge velocity or fuel consumption. Designing of the controller for course changing process is based on the Model Reference Adaptive System (MRAS) control theory, while as designing of the automatic course keeping process is based on the Self Tuning Regulator (STR) control theory. Simulation (using MATLAB software) in various disturbance conditions shows that in comparison with conventional PID autopilots, the designed autopilot has several notable advantages: higher course turning speed, lower swing of ship bow even in strong waves and winds, high accuracy of course keeping, shorter time of rudder actions smaller times of changing rudder direction.

• Journal of architectural history
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• v.7 no.4 s.17
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• pp.77-91
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• 1998

The theory of tectonic appeared in the midst of 19th century as German architects adopted new materials and structural technology, invented by creative engineers, into architectural design. This does not merely mean a technical problem but concern the redefinition of architecture in term of an aesthetic, cultural, and ontological identity. Furthermore it alluded to a desire on the part of architectural theorists to actualize artistic and spiritual goals out of new constructional necessities. Because of their complex discourse that assumed the possibility of communication between philosophical and technical aspects, between ideal and real concerns, tectonics becomes until now the most important issue in architecture. The concept of tectonic was intensively investigated by Gottfried Semper's and Karl B$\ddot{o}$tticher architectural writings. They contributed to clarify the principle aspects of tectonic within architectural, philosophical, and anthropological discourses of 19th century. Gottfried Semper stressed an understanding of how architecture took on physical form in earliest human culture. He placed great importance on the artistic expression of materials. But unlike Semper who argued the cladding of the structural frame by decorative wall system, Karl Botticher required maximum visibility of structural frame. This represents the different positions between Gottfried Semper and Karl Botticher

• Smart Structures and Systems
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• v.5 no.3
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• pp.209-221
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• 2009

A control algorithm for seismic protection of building structures based on the theory of variable structural control or sliding mode control is presented. The paper focus in the design of sliding surface. A method for determining the sliding surface by pole assignment algorithm where the poles of the system in the sliding surface are obtained on-line, based on the frequency content of the incoming earthquake signal applied to the structure, is proposed. The proposed algorithm consists of the following steps: (i) On-line FFT process is applied to the incoming part of the signal and its frequency content is recognized. (ii) A transformation of the frequency content to the complex plane is performed and the desired location of poles of the controlled structure on the sliding surface is estimated. (iii) Based on the estimated poles the sliding surface is obtained. (iv) Then, the control force which will drive the response trajectory into the estimated sliding surface and force it to stay there all the subsequent time is obtained using Lyapunov stability theory. The above steps are repeated continuously for the entire duration of the incoming earthquake. The potential applications and the effectiveness of the improved control algorithm are demonstrated by numerical examples. The simulation results indicate that the response of a structure is reduced significantly compared to the response of the uncontrolled structure, while the required control demand is achievable.

• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.54-69
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• 2012

Chan and Qi (SCM 8/3 (2003) 209) developed an innovative measurement method that aggregates performance measures in a supply chain into an overall performance index. The method is useful and makes a significant contribution to supply chain management. Nevertheless, it can be cumbersome in computation due to its highly complex algorithmic fuzzy model. In aggregating the performance information, weights used by Chan and Qi-which aim to address the imprecision of human judgments-are incompatible with weights in additive models. Furthermore, the default assumption of linearity of its scoring procedure could lead to an inaccurate assessment of the overall performance. This paper addresses these limitations by developing an alternative measurement that takes care of the above. This research integrates three different approaches to multiple criteria decision analysis (MCDA)-the multiattribute value theory (MAVT), the swing weighting method and the eigenvector procedure-to develop a comprehensive assessment of supply chain performance. One case study is presented to demonstrate the measurement of the proposed method. The performance model used in the case study relies on the Supply Chain Operations Reference (SCOR) model level 1. With this measurement method, supply chain managers can easily benchmark the performance of the whole system, and then analyze the effectiveness and efficiency of the supply chain.

• Advances in nano research
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• v.7 no.6
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• pp.431-442
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• 2019

Vibration analysis of carbon nanotubes (CNTs) is very essential field owing to their many promising applications in tiny instruments. In current study, the Eringen's nonlocal elasticity theory with clamped-clamped and clamped-free end conditions is utilized for the vibration analysis of armchair and zigzag SWCNTs. The Fourier method is utilized to solve the ordinary differential equation. The motion equation for this system is developed using a novel wave propagation method. Complex exponential functions have been used and the axial model depends on BCs that has been described at the edges of CNTs. The behavior of different nonlocal parameters is considered to find the vibrational frequency of SWCNTs. It is exhibited that the effect of frequencies against aspect ratio by varying the bending rigidity. It has been investigated that by increasing the nonlocal parameter decreases the frequencies and on increasing the aspect ratio increases the frequencies for both the tubes. To generate the fundamental natural frequencies of SWCNTs, computer software MATLAB engaged. The numerical results are validated with existing open text. Since the percentage of error is negligible, the model has been concluded as valid.