The University of TehranTehran

Engineering, Iran

The University of TehranTehran

Engineering, Iran
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Khodabandeloo B.,The University of TehranTehran | Khodabandeloo B.,Institute for Research in Fundamental Sciences | Khonsari A.,The University of TehranTehran | Khonsari A.,Institute for Research in Fundamental Sciences | And 2 more authors.
Integration, the VLSI Journal | Year: 2017

With aggressive scaling of CMOS technology, it is essential to consider chip temperature in all design levels of digital systems to improve chip reliability and leakage power consumption. In this paper, we present a two phase fixed-outline floorplanning framework that attempts to reduce the peak-temperature of the chip. The first phase distributes evenly the available dead space between the floorplan blocks of a chip, so as to reduce the peak-temperature. The second phase employs a two-stage convex optimization formulation to perform fixed-outline floorplanning such that minimizes the peak-temperature while satisfying physical constraints. To mitigate the time and computational complexity of capturing the temperature behavior, we present a less computational expensive analogous formulation that approximates the temperature of a block by its corresponding power density. Although, the corresponding power density formulation exhibits lower complexity the experimental results demonstrate its high degree of accuracy. Moreover, this formulation manages to achieve significant improvements in terms of peak-temperature and runtime for almost all of the test cases. We investigate the trade-off between peak-temperature and area as well and provide conditions that result in a reasonable reduction of peak-temperature with minimum increase of the dead space. © 2017


Nazarimofrad E.,Sina | Zahrai S.M.,The University of TehranTehran
Soil Dynamics and Earthquake Engineering | Year: 2016

Much research has been conducted in recent decades on structural control to improve the performance of different towers and high-rise buildings against severe earthquakes and strong winds. Most studies on building vibration control have been considered just two-dimensionally using shear frame models. In reality, most of the buildings might have irregular plans and thus experience torsion when subjected to earthquakes. Such torsion would further increase the structural response. On the other hand, some buildings are located on soft soil that would trigger the soil-structure interaction (SSI) effects required to be considered for design purposes. The main dynamic behavior parameters like natural frequencies, damping ratios and mode shapes would depend on construction site conditions and thus the SSI effects must be taken into account for buildings on soft soil. In this paper, a mathematical model is developed for calculating the seismic response of an irregular multi-story building equipped with active tendons. The SSI effect is then introduced by changing structure mass, stiffness and damping matrices. The model is employed to obtain the seismic response of 10-story buildings using active tendon with LQR algorithm. The building is modeled as a structure composed of members connected by rigid floor diaphragms with three degrees of freedom at each story; i.e. lateral displacements in two perpendicular directions and a rotation with respect to a vertical axis. Results showed that active tendons have low effects on the reduction of structural response when the building has been located on soft soils. © 2016 Elsevier Ltd

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