• Journal of KIISE:Computing Practices and Letters
• /
• v.7 no.2
• /
• pp.132-140
• /
• 2001

This paper proposes an efficient walktlu-ough animation from two images of the same scene. To make animation easily and fast, Tour Into the Picture(TIP) enables walkthrough animation from single image but lacks the reality of its foreground object when the viewpoint moves from side to side, and view morphing uses only 2D transition between two images but restricts its camera path on the line between two views. By combining advantages of these two image-based techniques, this paper suggests a new virtual navigation technique which enable natural scene transformation when the viewpoint changes in the side-to-side direction as well as in the depth direction. In our method, view morphing is employed only in foreground objects , and background scene which is perceived carelessly is mapped into cube-like 3D model as in TIP, so as to save laborious 3D reconstruction costs and improve visual realism simultaneously. To do this, we newly define a camera transformation between two images from the relationship of the spidery mesh transformation and its corresponding 3D view change. The result animation shows that our method creates a realistic 3D virtual navigation using a simple interface.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.14 no.6
• /
• pp.75-84
• /
• 2010

In current seismic design provisions, a reduced beam section with bolted web (RBS-B) connections is only permitted for intermediate moment frames (IMF). This study evaluated the seismic performance of steel moment resisting frame systems having RBS-B connections designed according to current seismic design provisions. For this purpose, 12 archetypal IMF systems having two different span lengths (9m, 6m) were designed considering two design load levels (SDC $C_{max}$, SDC $C_{min}$). A nonlinear analytical model that can simulate hysteretic behavior of an RBS-B connection was also developed in this study. The procedures specified in ATC 63 are used to conduct a seismic performance evaluation. Moreover, this study conducts the seismic performance evaluation of IMF systems designed according to a new design method proposed by the authors in the previous study. It was observed that several model frames designed according to current seismic design provisions did not provide satisfactory collapse margin ratios (ACMR). This study also showed that the model frames designed according to the new design procedures had a sufficient ACMR.

• Journal of the Korea Concrete Institute
• /
• v.23 no.1
• /
• pp.39-48
• /
• 2011

The present investigation evaluates the flexural behavior of pre-tensioned lightweight concrete beams under two-point symmetrical concentrated loads according to the variation of the partial prestressing ratio and the effective prestress of prestressing strands. The designed compressive strength of the lightweight concrete with a dry density of 1,770 $kg/m^3$ was 35 MPa. The deformed bar with a yield strength of 383 MPa and three-wire mono-strands with tensile strength of 2,040 MPa were used for longitudinal tensile reinforcement and prestressing steel reinforcement, respectively. According to the test results, the flexural capacity of pre-tensioned lightweight concrete beams increased with the increase of the partial prestressing ratio and was marginally influenced by the effective prestress of strands. With the same reinforcing index, the normalized flexural capacity of pre-tensioned lightweight concrete beams was similar to that of pre-tensioned normal-weight concrete beams tested by Harajli and Naaman and Bennett. On the other hand, the displacement ductility ratio of pre-tensioned lightweight concrete beams increased with the decrease of the partial prestressing ratio and with the increase of the effective prestress of strands. The load-displacement relationship of pre-tensioned lightweight concrete beam specimens can be suitably predicted by the developed non-linear two-dimensional analysis procedure. In addition, the flexural cracking moment and flexural capacity of pre-tensioned lightweight concrete beams can be conservatively evaluated using the elasticity theorem and the approach specified in ACI 318-08, respectively.

• Journal of Korean Association for Spatial Structures
• /
• v.7 no.2 s.24
• /
• pp.91-96
• /
• 2007

To improve the land use of urban, Construction of the circular steel column is required recently. The circular steel columns have a advantage for improving a load carrying capacity as wall as reducing a effective section area. However, the circular steel columns under service load, such as earthquake, shows a tendency to cause local buckling and large deformation. To prevent these phenomena, use of diaphragm is considered. It is reported that longitudinal stiffeners has a effect on improving a buckling and fatigue performance of steel structures. The research of effect on diaphragm is not sufficient. Under monotonic and cyclic loadings diaphragm make a important role to prevent local buckling and deformation of used steel structures. Therefore, influence of diaphragm on performance of used steel structures is investigated. In this study, the influence of diaphragm on seismic and deformation performance of circular steel piers was investigated by using elastic-plastic finite element analysis considered geometrical and material non-linearity. The seismic performance of circular steel columns was evaluated for analytical parameter of manufactured part. The seismic performance of circular steel columns was clarified by comparing an energy dissipation of circular steel piers.

• The Transactions of the Korea Information Processing Society
• /
• v.1 no.4
• /
• pp.427-437
• /
• 1994

Optimal static load balancing in star network configurations is considered. Three kinds of load balancing direction strategies are considered. First, a job arriving at the peripheral nodes may be processed either where it arrived(origin node) or transferred directly to central node Second, a job arriving at the central node may be processed there, or transferred to lightly loaded peripheral nodes. A nonlinear optimization problem is formulated. Using the optimal solution, an optimal load balancing algorithm is derived for the second load balancing strategy. Third a job arriving at the central node or a peripheral node may be processed either at origin node or transferred to another lightly loaded node (central or peripheral). A load balancing algorithm is derived for the third load balancing strategy. The effects of these three load balancing strategies are compared by numerical experiments. During the conduct of these in numerical experiments, several interesting phenomena were observed. The third load balancing strategy improved performance more than the first two other strategies. The second load balancing strategy, as a whole, resulted in only slightly improved performance. Finally, of the central node has larger processing power than the peripheral nodes, the first and third load balancing strategies produce equal performance improvement.

• Korean Chemical Engineering Research
• /
• v.46 no.4
• /
• pp.714-721
• /
• 2008

Chemical plants which consume lots of energy are not operating in the best conditions due to their own peculiar nonlinearity, instability, and diverse disturbances. In order to improve this, the plant wide optimization was performed. It is important to select the most appropriate number of decision variables which strongly affect the operating cost because there are too many decision variables which economically have an effect on plant wide. For instance, if all decision variables which can economically affect are applied in optimization and then the result of the optimization is applied to operation, a lot of operating conditions should be going to be changed. As a result of changing a plenty of operating conditions, the cost of the change will absolutely increase. Thus, in this study, the method of selecting the most appropriate decision variables which can influence on saving operation costs was presented in order to optimize plant wide. TPA (Terephthalic-acid) plant is considered as a case study. In other word, after modeling, the most proper decision variables was selected by examining the degree which decision variables influence on operating costs through sensitivity analysis. In TPA process, the three decision variables were selected by the presented method in this study. Then the plant was optimized by selected the decision variables. Consequently, it was seen that the plant are expected to save the 350 million won of energy annually without additional investment for facilities or remodeling of the plant.

• Nuclear Engineering and Technology
• /
• v.20 no.2
• /
• pp.88-104
• /
• 1988

The FUel Rod Analysis(FURA) code is developed using two-dimensional finite element methods for axisymmetric and plane stress analysis of fuel rod. It predicts the thermal and mechanical behavior of fuel rod during normal and load follow operations. To evaluate the exact temperature distribution and the inner gas pressure, the radial deformation of pellet and clad, the fission gas release are considered over the full-length of fuel rod. The thermal element equation is derived using Galerkin's techniques. The displacement element equation is derived using the principle of virtual works. The mechanical analysis can accommodate various components of strain: elastic, plastic, creep and thermal strain as well as strain due to swelling, relocation and densification. The 4-node quadratic isoparametric elements are adopted, and the geometric model is confined to a half-pellet-height region with the assumption that pellet-pellet interaction is symmetrical. The pellet cracking and crack healing, pellet-cladding interaction are modelled. The Newton-Raphson iteration with an implicit algorithm is applied to perform the analysis of non-linear material behavior accurately and stably. The pellet and cladding model has been compared with both analytical solutions and experimental results. The observed and predicted results are in good agreement. The general behavior of fuel rod is calculated by axisymmetric system and the cladding behavior against radial crack is used by plane stress system. The sensitivity of strain aging of PWR fuel cladding tube due to load following is evaluated in terms of linear power, load cycle frequency and amplitude.

• Journal of the Korea Concrete Institute
• /
• v.13 no.4
• /
• pp.371-378
• /
• 2001

Recently, the parameters, models, and experimentations, which evaluate the fracture properties of concrete, have been proposed by many researchers, and their developments allow us to analyze the non-linear and quasi-brittle fracture mechanisms. In this paper, a brief treatment of the fracture parameters was presented and the experiments of 3-point bending tests were conducted to compare J-integral($J_{Ic}$ /) with other parameters($K_{Ic}$ , $G_{v}$ , and $G_{F}$ ). The change of parameter values according to the width and notch length of concrete beam specimens was also considered. The load-displacement curves are used to experimentally measure concrete fracture toughness. From the results of experiment, it is noted that the value of $GF$ and tic decreases as the notch depth increases and $G_{F}$ is less sensitive than $J_{Ic}$ . Therefore, the former is more appropriate to use as the concrete fracture toughness parameter. The values of $v_{v}$ and $J_{Ic}$ increase when the width of concrete specimens increase from 75 mm to 150 mm. Therefore, the effects of specimen width need to be considered in determining the concrete fracture toughness.

• Journal of the Society of Disaster Information
• /
• v.15 no.4
• /
• pp.524-530
• /
• 2019

Purpose: In this paper, we construct a detailed three-dimensional interface element using a three-dimensional analysis program, and evaluate the composite behavior stability of the connector by applying physical properties such as the characteristics of general members and those of reinforced members Method: The analytical model uses solid elements, including non-linear material behavior, to complete the modeling of beam structures, circular flanges, bolting systems, etc. to the same dimensions as the design drawing, with each member assembled into one composite behavior linkage. In order to more effectively control the uniformity and mesh generation of other element type contact surfaces, the partitioning was performed. Modeled with 50 carbon steel materials. Results: It shows the displacement, deformation, and stress state of each load stage by the contact adjoining part, load loading part, fixed end part, and vulnerable anticipated part by member, and after displacement, deformation, The effect of the stress distribution was verified and the validity of the design was verified. Conclusion: Therefore, if the design support of the micro pile is determined based on this result, it is possible to identify the Vulnerable Parts of the composite behavior connector and the degree of reinforcement.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.16 no.4
• /
• pp.591-598
• /
• 2021

The digital phase-locked loops(DPLL) is a circuit used for phase synchronization and has been generally used in various fields such as communication and circuit fields. State estimators are used to design digital phase-locked loops, and infinite impulse response state estimators such as the well-known Kalman filter have been used. In general, the performance of the infinite impulse response state estimator-based digital phase-locked loop is excellent, but a sudden performance degradation may occur in unexpected situations such as inaccuracy of initial value, model error, and disturbance. In this paper, we propose a minimum variance finite impulse response filter with optimal horizon for designing a new digital phase-locked loop. A numerical method is introduced to obtain the measured value interval length, which is an important parameter of the proposed finite impulse response filter, and to obtain a gain, the covariance matrix of the error is set as a cost function, and a linear matrix inequality is used to minimize it. In order to verify the superiority and robustness of the proposed digital phase-locked loop, a simulation was performed for comparison and analysis with the existing method in a situation where noise information was inaccurate.