No abstract

One of the popular approaches in object boundary detecting and tracking is active contour models (ACM). This article presents a new balloon energy in parametric active contour for tracking a texture object in texture background. In this proposed method, by adding the balloon energy to the energy function of the parametric ACM, a precise detection and tracking of texture target in texture background has been elaborated. In this method, texture feature of contour and object points have been calculated using directional Walsh-Hadamard transform, which is a modified version of the Walsh-Hadamard. Then, by comparing the texture feature of contour points with texture feature of the target object, movement direction of the balloon has been determined, whereupon contour curves are expanded or shrunk in order to adapt to the target boundaries. The tracking process is iterated to the last frames. The comparison between our method and the active contour method based on the moment demonstrates that our method is more effective in tracking object boundary edges used for video streams with a changing background. Consequently, the tracking precision of our method is higher; in addition, it converges more rapidly due to it slower complexity.

In equivalent static analysis procedure, the design seismic force is affected by the response factor related to the inelastic behavior of the structure. This factor, whose value is used to calculate the amount of the energy damping, absorbed by the structure, depends on some parameters such as ductility and over strength. It is regarded as a constant coefficient for each type of structural systems in seismic codes. However, in dual structural systems, the effect of features like the geometry of the structure and lateral forces  resistance system on this coefficient is not taken into account. This research is aimed at investigating the effect of the arrangementand length of the shear wall in the plan on the response modification factor in dual concrete systems. To do this, 15 concrete buildings as high as 30 to 45 meters were analyzed by nonlinear static method, using Perform 3D software. The initial estimation of the shear wall length was based on resisting 75 percent of the design base shear force by the shear walls. Next, the over strength factors, ductility coefficients, and subsequently the response modification factors of the models were determined and compared to the value used in the design procedure, presented in ASCE7 code. The results indicated that the value of response modification factor, in comparison with the presented value in ASCE7 code, was varied between -18% to +25% over changing the arrangement of the shear walls, and increased for up to +32% by increasing the length of the shear wall in the plan as much as 100% in proportion to the original model.