• Computers and Concrete
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• v.33 no.6
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• pp.725-738
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• 2024

This study presents a macro-modeling procedure for nonlinear finite element analysis of reinforced and prestressed concrete panels under blast loading. The analysis procedure treats cracked concrete as an orthotropic material based on a smeared rotating crack model within the context of total-load secant stiffness-based formulation. A direct time integration method compatible with the analysis formulation is adapted to solve the dynamic equation of motion. Considerations are made to account for strain rate effects. The analysis procedure is verified by modeling 14 blast tests from various sources reported in the literature including a blast simulation contest. The analysis results are compared against those obtained from experiments, simplified single-degree-of-freedom (SDOF) methods, and sophisticated hydrocodes. It is demonstrated that the smeared crack macro-modeling approach is a viable alternative analysis procedure that gives more information about the structural behavior than SDOF methods, but does not require detailed micro-modeling and extensive material characterization typically needed with hydrocodes.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.3
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• pp.266-277
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• 2003

Every conceptual temporal rat relationship can be described using one of seven relations (before, meets, overlaps, during, starts, finishes, and equals ). The conceptual representation provides an efficient means for our multimedia authoring system to automatically fill in the necessary timing details. We developed a multimedia Presentation authoring system that supports a mechanism for conceptually representing the temporal relations of different media. Among the many editors that make up our system, the temporal relation editor provides users with an intuitive mechanism for representing the conceptual flow of a presentation by simple and direct graphical manipulations. Our system is based on the SMIL(Synchronized Multimedia Integration Language). The conceptual temporal relation editor and other editors of our system exchange their information in real-time and automatically generate SMIL codes through the SMIL Object Manager. Our system uses TRN(Temporal Relation Network) as its internal multimedia presentation representation. The TRN corresponds exactly to the structure seen in the graphical representation of the presentation. A parallel relationship found in a TRN can be collapsed into a single synchronization block. This facilitates the determination of the playing time of each component and can be the basic unit for reusability of already prepared blocks of presentation code.

• Journal of Korean Society for Geospatial Information Science
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• v.16 no.2
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• pp.67-76
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• 2008

Recently, one of the most outstanding technological characteristics of aerial survey is an application of Direct Georeferencing, which is based on the integration of main sensing sensors such as aerial camera or Lidar with positioning sensors GPS and IMU. In addition, a variety of digital aerial mapping cameras is developed and supplied with the verification of their technical superiority and applicability. In accordance with this requirement, the development of a multi-looking aerial photographing system is just making 3-D information acquisition and texture mapping possible for the dead areas arising from building side and high terrain variation where the use of traditional phptogrammetry is not valid. However, the development of a multi-looking camera integrating different sensors and multi-camera array causes some problems to conduct time synchronization among sensors and their geometric and radiometric calibration. The establishment of a test field for aerial sensor calibration is absolutely necessary to solve this problem. Therefore, this paper describes investigations for photogrammetric Test Field of foreign countries and suggest an establishment scheme for domestic test field.

• International Area Studies Review
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• v.12 no.3
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• pp.25-47
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• 2008

This paper tries to explore the impact of economic globalization on social capital accumulation. To investigate direct effect, we build a model and derive a proposition which can explain the relative decline in social capital brought about by market expansion. Besides direct effect, we also explore channel effect through democracy, government size, education attainment, and inequality. We estimate direct and channel effect of globalization using cross section of 65 countries data time period 1980-1999 using three-stage least squares(3SLS). Results are in line with predictions and clearly support that globalization significantly and negatively affects social capital accumulation. Channel effect also shows that globalization has a negative effect through aggravating income inequality while it has a positive effect through higher education attainment, higher level of democracy and larger government spending. Such a net negative channel effect reinforces our prediction. As a robustness check we estimate other sets of data and the result strongly supports our theory.

• Structural Engineering and Mechanics
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• v.50 no.6
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• pp.797-816
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• 2014

Cooling tower is analyzed as an assembly of layered nonlinear shell elements. Geometric representation of the shell is enabled through layered nonlinear shell elements to define the different layers of reinforcements and concrete by considering the material nonlinearity of each layer for the cooling tower shell. Modal analysis using Ritz vector analysis and nonlinear time history analysis by direct integration method have been carried out to study the effects of the inclination of the supporting columns of the cooling tower shell on its dynamic characteristics. The cooling tower is supported by I-type columns and ${\Lambda}$-type columns supports having the different inclination angles. Relevant comparisons of the dynamic response of the structural system at the base level (at the junction of the column and shell), throat level and at the top of the tower have been made. Dynamic response of the cooling tower is found to be significantly sensitive to the change of the inclination of the supporting columns. It is also found that the stiffness of the structure system increases with increase in inclination angle of the supporting columns, resulting in decrease of the period of the structural system. The participation of the stiffness of the tower in structural response of the cooling tower is fund to be dependent of the change in the inclination angle and even in the types of the supporting columns.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.36-41
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• 2020

Mechanical systems installed in transport devices, such as vehicles, airplanes, and ships, are mostly subject to translational accelerations at the joints during operations. This base acceleration excitation has a large influence on the performance of the system, therefore, its response must be well analyzed. However, the existing methods for dynamic analysis of structures have some limitations in use. This study presents a new numerical method using relative acceleration to solve these limitations. If the governing equation of motion is linear and the mass matrix, the damping matrix, and the stiffness matrix are constant over time in the finite element analysis, the proposed method can be applied to the transient behavior analysis and the harmonic response analysis of the structure. Because it is not necessary to introduce a virtual mass and the rigid body motions are removed from the analysis, it is possible to use not only the direct integration method in the time domain but also the mode superposition method to obtain the dynamic responses. This paper demonstrates with three examples how the present method is suitable for the dynamic analysis of a structure with multi-degree of freedom.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.3
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• pp.139-149
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• 2002

An explicit direct time integration method based solution algorithm is proposed to predict dynamic postbuckling response of thin plates. Based on the von Karman's plate equations and Marquerre's shallow shell theory, a rectangular plate finite element is formulated and utilized in this study. The element formulation takes into account geometrical nonlinearity and initial deflection of plates. The solution algorithm employs the central difference method. Using the computer program developed by the authors, dynamic postbuckling behavior of elastic thin plates under impact loading is investigated by considering the time variation of load and load duration. The efficiency of the proposed solution algorithm is examined through illustrative numerical examples.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.47.1-47.1
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• 2011

We studied the evolution of the two mass components system with NFW initial density distribution by direct integration of the Fokker-Planck equations. The low mass component is regarded the dark matter particles while the high mass component is assumed to be conglomerates of baryonic matter in order to depict the 'stars'. While the true mass ratio between these two types of particles should be extremely large, our adopted mass ratio is about 1000 beyond which the dynamical evolution and density distribution tend to converge. Since the dynamical evolution is dominated by the dynamical friction, the high mass component slowly moves toward the central part, and eventually undergoes the core collapse. The system reaches the core-collapse at about $7.1{\times}10^{-3}$ $t_{fh}$ in NFW models, where $t_{fh}$is the dynamical friction time at half-mass radius. The distribution of the high mass component is well fitted by the Sersic profiles or modified Hubble profile when the mass segregation is established. From these results, the surface brightness of elliptical galaxies may be explained by the high mass component experiencing dynamical friction by the dark matter particles. In order for the mass segregation to be effective within Hubble time, the mass of the luminous component should be greater than $10^5M_{\bigodot}$.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.7
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• pp.520-533
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• 2007

The CRM(Customer Relationship Management) is the business strategy model for higher profits and competitive power of the enterprise in a new business environment. The large-scale customer response service technique uses internet, e-mail, SMS (Short Message Service), Telephony service, DM(Direct Mail) by customer channel point. Recently, business model diversify for new contract and retaining existing customer to the effort for a profitable model of business. This paper is based on Avaya PDS(Predictive Dialing System) model for CRM bond center. If the number of "available" agents are less than the number of inbound channels, then there may be real-time response problems in PDS system implemented. The Organization cannot afford to have many agents in available mode because of the high cost of manpower. This paper provides two contributions to the study. First, we present Call Object Management Mechanism of Customer Channel integration for reduce outbound consulting and reduce CallBack data in the PDS. Second, we design and implement the proposed system. Our simulation results show analysis of old model and proposed model. The proposed model can be efficiently used in Large-scale CRM.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1408-1416
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• 1990

A powerful and efficient method for finding approximate solutions to initial-boundary-value problems in the transient coupled thermoelasticity is formulated in time domain using the finite element technique with time-marching strategy. The final system equations can be derived by the Guritin's variational principle using the definition of convolution integral. But, the finite element formulation for the equations of motion is modified by differentiating in time. Numerical results to some test problems are compared with analytical and other sophisticated approximate solutions. Stable responces are observed in all the given examples irrespective of incremental time steps and mesh shapes. In addition, it is shown that good numerical results are obtained even in coarser mesh or larger time step comparing to other numerical methods.