• Steel and Composite Structures
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• v.1 no.1
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• pp.75-96
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• 2001

Actual buckling curves are always characterised by the erosion of ideal buckling curves. In case of compact sections this erosion is due to the imperfections, while for thin-walled members, a supplementary erosion is induced by the phenomenon of coupled instabilities. The ECBL approach- Erosion of Critical Bifurcation Load - represents a practical and convenient tool to characterise the instability behaviour of thin-walled members. The present state-of-art paper describes the theoretical background of this method and the applications to cold-formed steel sections in compression and bending. Special attention is paid to the evaluation methods of erosion coefficient and to their validation. The ECBL approach can be also used to the plastic-elastic interactive buckling of thin-walled members, and the paper provides significant results on this line.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.583-587
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• 2015

Scenario-based learning (SBL) has been used in a variety of training situations across different disciplines. Despite its seemly widespread use in construction management discipline, very few attempts have been made to explore its effectiveness and the respective students' learning experience. Using a survey research design, this study aims to investigate students' perceptions on SBL approach in construction management courses. The specific objectives are: (i) to identify the characteristics of a favourable SBL environment, and (ii) to explore the students' learning experience and effectiveness of the SBL approach. The results show that the four characteristics of a favourable SBL environment are: effective team formulation, constant engagement with lecturer, working in a group, and incorporation of motivational incentive for participation. The students really appreciated the opportunities to apply concepts learnt in the lectures in their SBL group work. Also, they perceived that the SBL approach is effective in developing their reflective and critical thinking skills, analytic and problem-solving skills and their ability to work as a team. These findings should facilitate more critical approaches to similar form of teaching methods.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.575-581
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• 2011

A novel approach for analysis of criticality with respect to path and to activity in networks with fuzzy activity durations is proposed. After recalling the Yager ranking method, the relative degree of criticality of activities and paths are defined. An efficient algorithm based on path enumeration to compute the relative degree of criticality of activities and paths in networks with fuzzy durations is proposed. Examples of former researches are employed to validate the proposed approach. The proposed algorithm has been tested on real world project networks and experimental results have shown that the algorithm can calculate the relative degree of criticality of activities and paths in a reasonable time.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1454-1459
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• 2024

Researchers have applied theoretical and CFD models for years to analyze the fluidelastic instability (FEI) of tube arrays in steam generators and other heat exchangers. The accuracy of each approach has typically been evaluated using the discrepancy between the experimental critical flow velocity and the predicted value. In the best cases, the predicted critical flow velocity was within an order of magnitude comparable to the measured one. This paper revisits the quasi-steady approach for damping controlled FEI in a normal triangular array with a pitch ratio of P/d = 1.375. The method addresses the fluidelastic frequency at the stability threshold as an input parameter for the approach. The excellent agreement between the estimated stability thresholds and the equivalent experimental results suggests that the fluidelastic frequency must be included in the quasi-steady analysis, which requires minimal computing time and experimental data. In addition, the model allows a simple time delay analysis regarding flow convective and viscous effects.

• Journal of the Korean Mathematical Society
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• v.44 no.5
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• pp.1051-1063
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• 2007

The aim of this note is to advertise a method which turns out to be powerful enough to be used successfully in problems which are apparently unrelated. It is based on a modification of a construction that we first introduced in [2].

• Korean Journal of Mathematics
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• v.17 no.3
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• pp.331-340
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• 2009

We show the existence of nonconstant periodic solution for the nonlinear Hamiltonian systems with some nonlinearity. We approach the variational method. We use the critical point theory and the variational linking theory for strongly indefinite functional.

• Industrial Engineering and Management Systems
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• v.14 no.3
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• pp.221-235
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• 2015

Risk assessment is an important phase of risk management. It is the stage in which risk is measured thoroughly to achieve effective management. Some factors such as probability and impact of risk have been used in the literature related to construction projects. Because in high-rise projects safety issues are paramount, this study has tried to develop a quantifying technique that takes into account three factors: probability, impact and Safety Performance Index (SPI) where the SPI is defined as the capability of an appropriate response to reduce or limit the effect of an event after its occurrence with regard to safety pertaining to a project. Regarding risk-related literatures which cover an uncertain subject, the proposed method developed in this research is based on a fuzzy logic approach. This approach entails a questionnaire in which the subjectivity and vagueness of responses is dealt with by using triangular fuzzy numbers instead of linguistic terms. This method returns a Risk Critical Point (RCP) on a zoning chart that places risks under categories: critical, critical-probability, critical-impact, and non-critical. The high-rise project in the execution phase has been taken as a case study to confirm the applicability of the proposed method. The monitoring results showed that the RCP method has the inherent ability to be extended to subsequent applications in the phases of risk response and control.

• Journal of The Korean Association For Science Education
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• v.33 no.1
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• pp.144-160
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• 2013

This study is a proposal, which is the trial to explicate, in neurology, on how critical thinking as a creative method of sciences functions. The creative methods of sciences, even at present, are mostly the hypothetical insistences concerning with the logical processes of researches suggested from the philosophers of science; Popper, Kuhn, Hempel, or Lakatos. These insistences do excavate what process or approach can be scoped out of scientists' creativity. I call the tendency or approach of the researches, "Process Approach of Creativity (PAC)". From my view point, any PAC trial does not concern with how creative theories can actually be invented. On the other hand, this study is focused on the philosophical thinking abilities of scientists who invented new great theories. They mostly had some experiences to study philosophy while studying their science fields, thus had critical thinking abilities on their studies. From my point of view, critical thinking in philosophy raised questions as to their fundamental and basic (old) concepts and principles, and thus gave them new creative theories. I will try to explain this from the point of neurophilosophy. From the perspectives coming from "the state space theory of representation" of Paul & Patricia Churchland, the pioneers of neurophilosphy, the "creative theories" are the networks of topographic maps giving new comprehensive explanations and predictions. From these perspectives, I presuppose that the attitude of critical questioning revises the old networks of maps with back-propagation or feedback, and thus, is the generative power of searching new networks of maps. From the presupposition, I can say, it is important that scientists reflect on the basic premises in their academic branches for issuing out extraordinary creativity. The critical attitude of philosophy can make scientists construct the maps of new conceptual scheme by shaking the maps of the old basic premises. From this context, I am able to propose "Critical Thinking Approach of Creativity (CTAC)".

• The Journal of Information Systems
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• v.16 no.4
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• pp.177-194
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• 2007

This study is intended to identify critical success factors(CSF) of real-time enterprises(RTE) by using a policy leverage method of system dynamics. Since RTE is a new theoretical system that unifies existing theories or concepts in business management and information technology, it is not proper to employee a traditional statistical method. To obtain our research goal, causal maps of system dynamics are employed to abstract and arrange RTE information from previous studies. By using the commonness of policy leverage and critical success factors, CSFs for the RTE are deduced by substituting the leverage points on causal maps with necessary success factors to solve the problems. Since this is a new approach to identify success factors. it has some restrictions. Unlike the statistical methods, this approach explains only the directions of causalities and correlations. For the future research, a simulation tool of system dynamics can be employed to discover how each CSF is correlated to the successful implementation of RTE.

• Earthquakes and Structures
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• v.17 no.4
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• pp.387-398
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• 2019

On the basis that ground motions may arrive at a structure from any horizontal direction and that different directions of seismic incidence would result in different structural dynamic responses, this paper focuses on orienting the crucial seismic incidence of transmission tower-line systems based on the wavelet energy method. A typical transmission tower-line system is chosen as the case study, and two finite element (FE) models are established in ABAQUS, with and without consideration of the interaction between the transmission towers and the transmission lines. The mode combination frequency is defined by considering the influence of the higher-order modes of the structure. Subsequently, wavelet transformation is performed to obtain the total effective energy input and the effective energy input rate corresponding to the mode combination frequency to further judge the critical angle of seismic incidence by comparing these two performance indexes under different seismic incidence angles. To validate this approach, finite element history analysis (FEHA) is imposed on both FE models to generate comparative data, and good agreement is found. The results demonstrate that the wavelet energy method can forecast the critical angle of seismic incidence of a transmission tower-line system with adequate accuracy, avoiding time-consuming and cumbersome computer analysis. The proposed approach can be used in future seismic design of transmission tower-line systems.