• Earthquakes and Structures
• /
• v.6 no.1
• /
• pp.19-43
• /
• 2014

A risk assessment framework for evaluating building structures is implemented in this study. This framework allows considering sources of uncertainty both on structural capacity and seismic demand. In particular randomness on seismic load, incident angle, material properties, floor mass and structural damping are considered; in addition the choice of fibre modelling versus plastic hinge model is also considered as a source of uncertainty. The main objective of this work is to study the contribution of these sources of uncertainty on the fragilities of steel and steel-reinforced concrete composite 3D building structures. The fragility curves are expressed in the form of a two-parameter lognormal distribution where vertical statistics in conjunction with metaheuristic optimization are implemented for calculating the two parameters.

• Structural Engineering and Mechanics
• /
• v.67 no.4
• /
• pp.337-346
• /
• 2018

The purpose of this study is to investigate thermal post-buckling analysis of a laminated composite beam subjected under uniform temperature rising with temperature dependent physical properties. The beam is pinned at both ends and immovable ends. Under temperature rising, thermal buckling and post-buckling phenomena occurs with immovable ends of the beam. In the nonlinear kinematic model of the post-buckling problem, total Lagrangian approach is used in conjunction with the Timoshenko beam theory. Also, material properties of the laminated composite beam are temperature dependent: that is the coefficients of the governing equations are not constant. In the solution of the nonlinear problem, incremental displacement-based finite element method is used with Newton-Raphson iteration method. The effects of the fibber orientation angles, the stacking sequence of laminates and temperature rising on the post-buckling deflections, configurations and critical buckling temperatures of the composite laminated beam are illustrated and discussed in the numerical results. Also, the differences between temperature dependent and independent physical properties are investigated for post-buckling responses of laminated composite beams.

• Journal of Technology Innovation
• /
• v.11 no.2
• /
• pp.239-281
• /
• 2003

This study explored the patterns of activities and interactions among participants in the adoption process of a new system innovation, ADSL, in Korea, using an integrative framework of innovation system and strategic decision-making process for uncertainty reduction. An in-depth case analysis was undertaken to identify the adoption process of ADSL innovation, as a case in point, in conjunction with activities and interactions among related parties such as government, service providers, equipment suppliers, and content providers. The results of case analysis revealed that as the level of uncertainty in the adoption of ADSL innovation decreases, the focus of decision-making activities moves from scoping, to searching, to evaluating and to committing. Also this study found that at the early stage of ADSL adoption with higher level of uncertainty, government plays a pivotal role in coordination of related parties to participate in the innovation process, while service providers replaced this role at later stage of innovation with lower level of uncertainty. This study discussed theoretical and policy implications for the adoption of new system innovations with varying degrees of uncertainty.

• Journal of Communications and Networks
• /
• v.12 no.6
• /
• pp.616-623
• /
• 2010

In this paper, exact closed-form expressions for outage probability and bit error probability (BEP) are presented for multi-hop decode-and-forward (DF) relaying schemes in conjunction with cooperative diversity, in which selection combining technique is employed at each node. We have shown that the proposed protocol offers remarkable diversity advantage over direct transmission as well as the conventional DF relaying schemes with the same combining technique. We then investigate the system performance when different diversity schemes are employed. It has been observed that the system performance loss due to selection combining relative to maximal ratio combining is not significant. Simulations are performed to confirm our theoretical analysis.

• Proceedings of the KIEE Conference
• /
• 1999.07c
• /
• pp.1514-1516
• /
• 1999

This paper presents a sequential framework that calculates the total transfer capabilities of power transmission systems. The proposed algorithm enhances the Power System Transfer Capability Program (PSTCP) in conjunction with the Continuation Power Flow(CPF) that is used for steady-state voltage stability analysis and modified Arnoldi-Chebyshev method that calculates rightmost eigenvalues for small signal stability analysis. The proposed algorithm is applied to IEEE 39-bus test system to calculate TTC.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.4
• /
• pp.631-641
• /
• 1988

Computational procedures associated with finite element nonlinear analysis of plane frame structures were examined and new solution schemes were suggested. Element stiffness matrix was derived from the principle of virtual displacements. Geometric and material nonlinearities were considered in the formulation. Solution method was based upon the constant displacement length method in conjunction with the Newton-Raphson method. New solution schemes were introduced in determining the initial load increment and the sign of load increments and predicting the length of displacement increment to improve user convenience, efficiency and stability. Numerical experiments were performed for several typical problems and suggested schemes were found efficient and convenient for analyzing nonlinear frame structures.

• Computational Structural Engineering
• /
• v.4 no.3
• /
• pp.107-115
• /
• 1991

A probabilistic-Fuzzy model for seismic hazard analysis is developed. The proposed model is able to reproduce both the randomness and the imprecision in conjunction with earthquake occurrences. Results-of this research are (a) membership functions of both peak ground accelerations associated with a given probability of exceedance and probabilities of exceedance associated with a given peak ground acceleration, and (b) characteristic values of membership functions at each location of interest. The proposed probabilistic-fuzzy model for assessment of seismic hazard is successfully applied to the Wasatch Front Range in Utah in order to obtain the seismic maps for different annual probabilities of exceedance, different peak ground accelerations, and different time periods.

• Journal of the Korea Safety Management & Science
• /
• v.11 no.2
• /
• pp.117-126
• /
• 2009

We develop methods for propagating and analyzing EPCI(Extended Process Capability Index) by using the error type that classifies into accuracy and precision. EPCI developed in this study can be applied to the three combined processes that consist of production, measurement and calibration. Little calibration work discusses while a great deal has been studied about SPC(Statistical Process Contol) and MSA(Measurement System Analysis). EPCI can be decomposed into three indexes such as PPCI(Production Process Capability Index), PPPI(Production Process Performance Index), MPCI(Measurement PCD, and CPCI(Calibration PCI). These indexs based on the type of error classification can be used with various statistical techniques and principles such as SPC control charts, ANOVA(Analysis of Variance), MSA Gage R&R, Additivity-of-Variance, and RSSM(Root Sum of Square Method). As the method proposed is simple, any engineer in charge of SPC. MSA and calibration can use efficientily in industries. Numerical examples are presentsed. We recommed that the indexes can be used in conjunction with evaluation criteria.

• Journal of the Korean Society of Safety
• /
• v.15 no.2
• /
• pp.103-110
• /
• 2000

This paper deal with the stability evaluation and suggestion of progressive failure slope in biotite granite area of Andong. Based on geological site investigation and field test, stability analysis of slope was performed in conjunction with limit equilibrium methods and stereographic projection. Additionally, initial design and construction procedure was critically evaluated. Series of the slope stability analysis reveals the detection of local wedge and plane failure under the current slope condition. It is additionally appeared that a certain synthetic behavior of circle and plane failure exists on the right spot where the overall failure's going in progress. In order to construct more stable slope based on the suitability for the real state of the slope circumstances, this study issues a solution to eliminate the primary factors which cause the instability, by means of the grade of weathering and RMR classification of rock mass.

• Steel and Composite Structures
• /
• v.26 no.6
• /
• pp.733-743
• /
• 2018

This paper presents post-buckling responses of a simply supported laminated composite beam subjected to a non-follower axially compression loads. In the nonlinear kinematic model of the laminated beam, total Lagrangian approach is used in conjunction with the Timoshenko beam theory. In the solution of the nonlinear problem, incremental displacement-based finite element method is used with Newton-Raphson iteration method. There is no restriction on the magnitudes of deflections and rotations in contradistinction to von-Karman strain displacement relations of the beam. The distinctive feature of this study is post-buckling analysis of Timoshenko Laminated beams full geometric non-linearity and by using finite element method. The effects of the fibber orientation angles and the stacking sequence of laminates on the post-buckling deflections, configurations and stresses of the composite laminated beam are illustrated and discussed in the numerical results. Numerical results show that the above-mentioned effects play a very important role on the post-buckling responses of the laminated composite beams.