Abstract

In this paper, we propose an accurate and computationally efficient Gradient Boosting approach for the estimation of statistical variations aware leakage power and propagation delay in the CMOS/FinFET standard digital cells. The proposed model estimates the leakage power and propagation delay w.r.t variations in process, temperature (−55°C to 125°C) and supply voltage(±10% variations). The distinguishing feature of the proposed approach is its compatibility with both CMOS and FinFET technologies. Moreover, the performance of the proposed model is consistent with various technology nodes. Exhaustive tests report an average error of <1% in 16nm CMOS and FinFET standard digital cells w.r.t analog HSPICE simulations with several orders increase in computational speed. Further, the complex cell estimation can be carried out through precharacterized standard cells abstaining longer simulations.

Abstract

Rapid urbanization and associated land-use changes in cities cause an increase in the demand for electricity by altering the local climate. The present study aims to examine the variations in total energy and cooling energy demand in a calibrated building, caused by urban heat island formation over Delhi. The study used Sentinel-2A multispectral imagery for land use and land cover (LULC) of mapping of Delhi, and Moderate Resolution Imaging Spectroradiometer (MODIS) imagery for land surface temperature (LST) mapping during March 2018. It was observed that regions with dense built-up areas (ie, with built-up area greater than 90%) had a higher annual land surface temperature (LST), ie, 293.5 K and urban heat island intensity (UHII) ranging from 0.9 K-5.9 K. In contrast, lower annual values of LST (290K) and UHII (0.0-0.4 K) were observed in regions with high vegetation cover (53%). Statistical analysis reveals that a negative correlation exists between vegetation and nighttime LST, which is further confirmed by linear regression analysis. Energy simulations were performed on a calibrated building placed at three different sites, identified on the basis of land use and land cover percentage and annual LST. Simulation results showed that the site located in the central part of Delhi displayed higher annual building energy consumption (425.12 MWh/y) compared to the site located in the rural periphery (381.13 MWh/y). For all the three sites, the maximum electricity consumption and the cooling load were observed in the summer season, while the minimum were seen in the winter season. The study indicates that UHI formation leads to …

Abstract

Approximate Computing has paved way for elaborate savings in design area and latency of modern system architectures processing images or signals, by a deliberate yet tolerable loss of functional accuracy. This paper thus proposes a design of an approximate multiplier based on the efficient Toom-Cook algorithm, that has a lower complexity of O(N logd(zd−1) ) than O(N 2 ), for order d. Inherent integer divisions in the algorithm has restricted its feasibility in hardware, unless without suitable approximation. On an average, the proposed multiplier achieves 53%, 18% and 57% improvements in area, delay and power only with less than 1% mean error. Owing to these benefits due to lower computational complexity, the multiplier can be configured to achieve significant savings with a high quality output and that suits well to the nature of the speech processing systems, hence the design works well for the epoch extraction system in speech.

Abstract

This brief presents a novel low-power and area-efficient LDO that satisfies all primary requirements of power mapping for a Power Management IC (PMIC). The design introduces a dynamically biased feedback resistor which responds instantly to the output voltage variations, thereby achieving better load transient behavior. Besides, the employed adaptive-biasing technique contributes in architectural transformation to attain stability over a wider range of load currents (0–100mA). It provides a regulated voltage of 1.87V from a supply ranging from 1.92V to 3.6V with a reported load and line regulation of 0.00136mV/mA and 0.078mV/V respectively. Moreover, the circuit potentially supports the load transients either from 0A to 100mA or 100mA to 0A with a rise and fall times of 10 μs. The achieved overshoot and undershoot values are 160mV and 154mV respectively. Hence, it demonstrates a substantial steady-state and transient performance with low-power thus making it suitable for battery-operated portable devices.

Abstract

Construction of buildings without keeping enough setback from plot boundary is very common practise in India. This lead to very closely spaced buildings with practically zero or few mm gap between them. The intension behind this is to utilize the maximum plot area, without knowing the consequences of damage due to pounding during moderateto-severe earthquake shaking. In this study, an attempt is made to check the adequacy of separation distance clause of IS 1893: 2016 and also a comparison is made with similar clauses in international codes of practise. For this purpose, four low to mid-rise RC buildings located in seismic zone IV were designed as per IS 456: 2000 and IS 1893: 2016. These buildings are assumed to be closely spaced with each other, in pair of two, for four different cases. Further, the linear and non-linear time history analysis (NLTHA) were carried out by considering ground motion time histories of three moderate earthquakes recorded in India. From the study, it was found that the separation distance clauses prescribed in IS 1893-2016 are on conservative side.

Abstract

This work presents a highly accurate current reference of 66nA for ultra-low power applications. A very low figure-of-merit (FOM) of 1.3501ppm/°C 2 is achieved on consuming a minimal quiescent current of 199.37nA. To cancel out process variations, the current subtraction technique is employed and a β-multiplier is used to compensate for mobility (μ) and threshold voltage (V th ). In addition, curvature compensation technique backed by PTAT and CTAT current cancellation is adopted to attain a lower temperature coefficient (TC). Hence, an imperceptible variation of accuracy with temperature and supply variations across all process corners is attained. An adopted trimming scheme further minimizes the overall process spread to ±1.515% without compromising on accuracy. Accordingly, a TC of 67.04ppm/°C over a wide temperature range of −50° C to 100° C is obtained. Furthermore, 1.413%/V line sensitivity (LS) in the supply range of 1.38V to 3V is observed. Low power consumption of 275.13nW@1.38V facilitates its use in high-performance low power applications.

Abstract

In this study, a three-dimensional, four-storied, reinforced concrete (RC) building is designed for seismic zone-IV and seismically evaluated for different infill configurations along with consideration of openings in infills to develop a realistic model. Four models are considered, ie model I (full RC-infilled frame without lintel beam), model II (bare frame without lintel beam), model III (full RC-infilled frame with lintel beam) and model IV (bare frame with lintel beam). In this study, we have evaluated the effect of lintel beams on response reduction factor of the frame structure. The nonlinear static adaptive pushover analysis has been done using Seismostruct program. In seismic design, the response reduction factor (R-factor) reduces from the elastic to inelastic strength. The R-factor is one of the design tools to show the level of inelasticity in a structure and so it has significant importance in the earthquake engineering field. The response reduction factor mainly consists of ‘ductility reduction factor’and ‘over strength factor’, which are evaluated from static adaptive pushover analysis. Ultimately the response reduction factor is obtained for the building and compared with the value recommended by IS 1893 Part-1 (2016). The results depict that the

Abstract

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Abstract

An earthquake Mw7.8 occurred on 25 April 2015 in a seismically dominant area of Nepal. No major earthquakes (>Mw7.0) were recorded in the past two decades, though Nepal is one of the active seismic regions in the world. The combined effect of the main event and the aftershocks, which are temporally distributed over 40 days, has led to a huge devastation, killing thousands of people in the epi-central area. A complete seismic catalog and influencing parameters such as type of fault, epi-central/hypo-central distance, type of soil are required for a region to assess seismic hazard scenario. The seismic hazard can be represented in terms of Peak Ground Acceleration (PGA), which is the most widely used parameter in strong motion studies. The main objective of this paper is to understand the characteristics of ground motion of the 2015 Nepal earthquake. Since the available ground motion records are limited, an attempt has been made to generate ground motion records using a modified semi-empirical approach. Contour maps of PGA and intensity have also been generated. It is observed that around 22% of buildings experienced an intensity of VI on MMI scale at Bageswari mandal. A few buildings have experienced an intensity of VII in Thankot, Seuchatar, Satikhel, Mahadevathan, Indrayani, Chhaimale, and Balambu.

Abstract

Damage index models are used for quantification of damage in any numerical model of a building. While using any particular damage model there is high possibility that it might give similar result for two identical structures, each having different attributes. So, though currently available damage index models precisely quantify damage in the structure but fails to identify the reason or attributes/irregularities present in it. Therefore, for quantitative assessment, a unique aspect should be used which will depend on structural as well as architectural features. This paper presents new method for quantification of damage for reinforced concrete (RC) moment resisting framed (MRF) structures using the pattern of hinge formation in structure when it is subjected to a monotonic loading. A two-dimensional RC MRF structures with different building irregularities were modeled. As a primary step to estimate the damage from the pattern of hinge formation, it is necessary to understand and study the relation between damage and hinge pattern. For this purpose, energy-based damage index model is used. The relation between damage index and pattern of hinge formation is studied with the help of regression analysis. A multiple regression analysis is performed taking damage index as dependent variable and the number of hinges formed in each damage state as independent variables. The paper also discusses two different approaches for regression analysis determining the corresponding coefficients. The regression analysis resulted in an equation which can approximately quantify the damage in the structure using total number of hinges formed in each