• Magazine of korean Tunnelling and Underground Space Association
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• v.21 no.2
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• pp.117-129
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• 2019

Tunnelling in urban environments is very common nowadays as large cities are expanding and transportation demands require the use of the underground space for creating extra capacity. Inevitably, any such new construction may have significant effects on existing nearby infrastructure and therefore relevant assessment of structural integrity and soil-structure interaction is required. Foundation piles can be rather sensitive to nearby tunnel construction and therefore their response needs to be evaluated carefully. Although detailed three-dimensional continuum finite element analysis can provide a wealth of information about this behaviour of piles, such analyses are generally very computationally demanding and may require a number of material and other model parameters to be properly calibrated. Therefore, relevant simplified approaches are used to provide a practical way for such an assessment. This paper presents a simple method where the pile is modelled with beam finite elements, pile-soil interaction is modelled with soil springs and tunnelling-induced displacements are introduced as an input boundary condition at the end of the soil springs. The performance of this approach is assessed through some examples of applications.

• Structural Engineering and Mechanics
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• v.83 no.6
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• pp.729-744
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• 2022

In this paper, an analytical formulation is proposed to predict the vertical vibration response due to the pedestrian walking on a footbridge considering the human-structure interaction, where the footbridge and pedestrian are represented by the Euler beam and linear oscillator model, respectively. The derived coupled equation of motion is a nonlinear fourth-order partial differential equation. An uncoupled solution strategy based on the combined weighted residual and perturbation method) is proposed to reduce the tedious computation, which allows the separate integration between the bridge and pedestrian subsystems. The theoretical study demonstrates that the pedestrian subsystem can be treated as a structural system with added mass, damping, and stiffness. The analysis procedure is then applied to a case study under the conditions of single pedestrian and multi pedestrians, and the results are validated and compared numerically. For convenient vibration design of a footbridge, the simplified peak acceleration formula and the idea of decoupling problem are thus proposed.

• Asia Marketing Journal
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• v.18 no.4
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• pp.139-160
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• 2017

Despite widespread awareness of the importance of a middle-aging and older consumer market, it is surprising that very little research has been conducted on their in-home shopping behavior. Therefore, this study focused on middle-aging and older female television home shoppers and examined the effects of persuasive mentions of the show host and parasocial interaction on social involvement, perceived loneliness, mood, perceived risk and unplanned buying tendency. A total of 109 middleaged and older female television shoppers responded. Results of path analysis revealed that persuasive mentions did not influence parasocial interaction. However, as middle-aging and older consumers more para-socially interacted with the host, they were likely to use television shopping for alleviating loneliness. Practical and theoretical implications were discussed.

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.188-189
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• 2005

• The Journal of Information Systems
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• v.27 no.3
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• pp.161-180
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• 2018

Purpose One of the success factors of information system projects is to reduce requirements uncertainty through user engagement. So, in many recent IS development environment, a business analyst or business analysts are positioned between users and developers to drive user engagement to reduce requirements uncertainty. But, there are few studies that research about the competencies of business analysts for training and staffing. So, this study analyzed which underlying and practical competencies that positively influence user engagement are required. Design/methodology/approach The level of underlying and practical competencies required for business analysts and the level of user enagement in the IS development environment are collected through the survey. And, the causal relationship between the construct concepts which are underlying competencies, practical competencies and the user participation is analzed through the PLS analysis. Findings The results of this study show that the practial competencies of business analysts that positively have a significant impact on user engaement were studied as requirements development skills. Additionally, the underlying competencies of business analysts which have a significant impact on requirements development skills were examined as business knowledge and interaction skills rather than technical knowledge and communication skills.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.5 no.3
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• pp.230-245
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• 2005

In this paper, we develop a gesture-based input device equipped with accelerometers and gyroscopes. The sensors measure the inertial measurements, i.e., accelerations and angular velocities produced by the movement of the system when a user is inputting gestures on a plane surface or in a 3D space. The gyroscope measurements are integrated to give orientation of the device and consequently used to compensate the accelerations. The compensated accelerations are doubly integrated to yield the position of the device. With this approach, a user's gesture input trajectories can be recovered without any external sensors. Three versions of motion tracking algorithms are provided to cope with wide spectrum of applications. Then, a Bayesian network based recognition system processes the recovered trajectories to identify the gesture class. Experimental results convincingly show the feasibility and effectiveness of the proposed gesture input device. In order to show practical use of the proposed input method, we implemented a prototype system, which is a gesture-based remote controller (Magic Wand).

• Structural Engineering and Mechanics
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• v.68 no.2
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• pp.159-170
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• 2018

This paper aims to develop response modification factors for stiffness degrading structures by incorporating soil-structure interaction effects. A comprehensive parametric study is conducted to investigate the effects of key SSI parameters, natural period of vibration, ductility demand and hysteretic behavior on the response modification factor of soil-structure systems. The nonlinear dynamic response of 6300 soil-structure systems are studied under two ensembles of accelograms including 20 recorded and 7 synthetic ground motions. It is concluded that neglecting the stiffness degradation of structures can results in up to 22% underestimation of inelastic strength demands in soil-structure systems, leading to an unexpected high level of ductility demand in the structures located on soft soil. Nonlinear regression analyses are then performed to derive a simplified expression for estimating ductility-dependent response modification factors for stiffness degrading soil-structure systems. The adequacy of the proposed expression is investigated through sensitivity analyses on nonlinear soil-structure systems under seven synthetic spectrum compatible earthquake ground motions. A good agreement is observed between the results of the predicted and the target ductility demands, demonstrating the adequacy of the expression proposed in this study to estimate the inelastic demands of SSI systems with stiffness degrading structures. It is observed that the maximum differences between the target and average target ductility demands was 15%, which is considered acceptable for practical design purposes.

• Korean Journal of Human Ecology
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• v.10 no.2
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• pp.215-224
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• 2001

Creativity is a trait necessarily demanded in highly industrial and information oriented society. Accordingly, we should develop creativity through school education. The purpose of this study is to inquire a conceptual model and teaching method for developing creative problem solving skills in home economics education which can work at a platform for the curriculum developer. Although many definitions of creativity consider cognitive aspect more, personal or affective aspect is heavily involved with creativity. Therefore, creativity is a dynamic system which cooperates many contrasting and dialectic components in personal and cognitive aspects. The function of creativity is dependent on diverse environmental system. Environments influence on the extent of the development of creativity. Thus, the person-situation interaction model devised by Woodman and Schoenfeldt, integration of cognitive, affective, and situational aspects, is suggested as a conceptual model for teaching creativity in home economics education. The practical reasoning teaching model is suggested as a teaching method for developing creative problem solving skills in home economics education. The components of creative problem solving which involved with practical reasoning process are general knowledge and skills, specific knowledge and skills, divergent thinking skills, motivation and motives, and critical thinking skills.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.1
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• pp.49-56
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• 1992

This study was carried out to investigate the mechanical behaviour of the plate on a Winkler's foundation according to the soil-structures relative stiffness and the applicability of the conventional analysis method. For the above purpose, Winkler's constant of 4, 15, 25 and 100kg/$cm^2$/cm was considered and the plate thickness of 20, 30, 50, 100 and 150cm was adopted. Results obtained from the numerical examples are summarized as follow: 1. The effects of elastic foundation is considerable for plates with small flexural rigidity. 2. As the Winkler's constant increases, the bending moment in the plate becomes localized near the loading point. 3. The stresses evaluated by the conventional method not correct even for rigid ground such as rock. 4. If the relative stiffness of the plate is very large, for example the plate thickness is larger than 100cm, the conventional analysis method can be justified for the design purposes. 5. On assumption the flexural rigidity of the plate is infinite, the interaction of soil and plate can be ignored in design consideration. The numerical examples in this paper show that when the plate thickness is more than 100cm, the effects of elastic foundation almost disappear. In practical design, soil-plate interaction should be taken into account, because the 100cm-thickness of the plate will not be practical value in usual sites.

• Geomechanics and Engineering
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• v.17 no.1
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• pp.1-9
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• 2019

This paper proposes a new numerical approach to model geocell reinforced soils, where the geocell is described as membrane elements and the complex interaction between geocell and soil is realized by coupling their degrees of freedom. The effectiveness and robustness of this approach are demonstrated using two examples, i.e., a geocell-reinforced foundation and a large scale retaining wall project. The first example validates the approach against established solutions through a comprehensive parametrical study to understand the influence of geocell on the improvement of bearing capacity of foundations. The study results show that reducing the geocell pocket size has a strong effect on improving the bearing capacity. In addition, when the aspect ratio maintains the same value, the bearing capacity improvement with increasing geocell height is insignificant. Comparing with the field monitoring and measurement in the project, the second example investigates the application of the approach to practical engineering projects. This paper provides a practically feasible and efficient modelling approach, where no explicit interface or contact is required. This allows geocell reinforced soils in large scale project can be effectively modelled where the mechanism for complex geocell-soil interaction can be explicitly observed.