Sharif Digital Repository

The eccentric bracing system equipped with vertical links is capable of providing high levels of stiffness, strength and ductility, and therefore, can be efficiently used for seismic retrofit of existing structures. This study aims to investigate the seismic reliability of steel moment-resisting frames retrofitted by this system using a novel combined series–parallel system approach. The seismic response of 4, 8 and 12-storey steel moment-resisting frames (MRFs) are evaluated under a set of design basis earthquakes (DBE) before and after retrofitting intervention. Adopting an engineering demand parameter approach (EDP-Based) for reliability assessment and development of analytical models for... 

Recent studies have indicated the need of considering aftershocks in the seismic design/assessment of structures. This article investigates the effect of sequential mainshock and aftershock earthquakes on eccentrically braced steel frames with vertical energy-absorbing links. To achieve this, 4, 8 and 12-storey frame buildings are modelled in Perform3D® software considering non-linear behaviour of materials and components. The frames are subjected to a set of 12 main earthquake records corresponding to the required hazard level, and then subsequent aftershocks are applied using incremental dynamic analysis (IDA). To reduce the computational cost, an alternative approach is also adopted by... 

Analog computing has emerged as a promising candidate for real-time and parallel continuous data processing. This article presents a reciprocal way for realizing asymmetric optical transfer functions (OTFs) in the reflection side of the on-axis processing channels. It is rigorously demonstrated that the presence of cross-polarization exciting normal polarizabilities (CPENPs) of a reciprocal metasurface circumvents the famous challenge of Green's function approach in implementation of on-axis reflective optical signal processing while providing dual computing channels under orthogonal polarizations. Following a comprehensive theoretical discussion and as a proof of concept, an all-dielectric... 

The present study examines the performance of three powerful methods including the original differential evolution (DE), the improved differential evolution (IDE), and the winner of the CEC-2014 competition, LSHADE, in addition to the covariance matrix adaptation evolution strategy (CMAES) for size optimization of truss structures under natural frequency constraints. Despite the abundant researches on novel meta-heuristic algorithms in the literature, the application of CMAES, one of the most powerful and reliable optimization algorithms, on the optimal solution of the truss structures has received scant attention. For consistent comparison between these algorithms, four stopping criteria... 

This study introduces a novel Bayesian framework for online and real-time vibration control of beam type structures, which represent a comprehensive control system associated with input-state algorithms. Control design systems typically require knowledge of system states, which in structures are displacements and velocities at some degrees of freedom. Currently, full-field measurements of displacements and velocities in large structural systems are not feasible. Also, properties of the moving inertial loads as key parameters in control designs are assumed known; however, in practice, measuring their characteristics is a challenging issue. As a remedy, an observer is required to estimate... 

This study introduces a simple and efficient method to determine the peak floor acceleration (PFA) at different performance levels for three types of plane reinforced concrete (RC) structures: moment-resisting frames (MRFs), infilled–moment-resisting frames (I-MRFs), and wall-frame dual systems (WFDSs). By associating the structural maximum PFA response with the deformation response, the acceleration-sensitive nonstructural components, and the building contents, can be designed to adhere to the performance-based seismic design of the supporting structure. Thus, the proposed method can accompany displacement-based seismic design methods to design acceleration-sensitive nonstructural elements... 

Given the importance of reducing energy consumption and the challenge of heat generation in classic CMOS circuits, adiabatic circuits are believed as an appropriate alternative. Most of the adiabatic circuit families come with a dual-rail structure, which provides them with an inherent hardware redundancy. Although this redundancy could be used for improving their reliability, no studies have been previously conducted to exploit this feature. In this regard, in this paper, we show that by exploiting the inherent hardware redundancy in adiabatic circuits, their reliability could be improved, while imposing a relatively low amount of energy overhead. Subsequently, with utilizing the outcome... 

Despite the advantages of employing an electric propulsion system in All-Electric Ships (AES), additional power fluctuation sources have emerged in the ship power system as a result. Since the propellers are the primary power consumers in the AES, these fluctuations may significantly affect its power system power quality. Thus, for optimal performance of the ship power system, these fluctuations need to be rigorously investigated at the design level of vessels. Waves collision is one of the critical conditions where propellers inject power fluctuations into the ship power system. Therefore, a comprehensive model is essential to analyze the propellers in-and-out-of-water effect on the ship... 

The technology world is developing fast with the developments made in the hardware and software areas. Considering that privacy and security of telemedicine applications are among the main necessities of this industry, as a result, there is a need to use lightweight and practical algorithms to be used in applications in the field of telemedicine, while security have the least negative impact. The distinct and contradicting components in the design and implementation of the cryptography algorithm, to achieve various objectives in medicine-based applications, have made it a complicated system. It is natural that, without identifying the components, indices, and properties of each system... 

We have investigated the usage of a Dielectric Barrier Discharge (DBD) plasma actuator to improve the aerodynamic performance of an offshore 6 MW wind turbine. By controlling the aerodynamic load combined with pitch angles of 2, 5, and 10 degrees, we studied the plasma actuator effect on the overall harvested power. Actuators were installed in single and tandem configurations in different chord-wise locations to find the optimum design. The improved phenomenological model developed by authors was used in an analysis to simulate the interaction of the electrostatic field, the ionized particles and the fluid flow. A design software was used to estimate the harvested power of the real 3D blade.... 

Linear resolvers are position sensors that are being used in a wide range of applications for linear motion systems. The electromagnetic design of a linear resolver, similar to any other electromagnetic device, demands an accurate, functional, and fast tool. While the finite element method (FEM) is considered the most accurate tool for electromagnetic analysis, it is not a good candidate for an optimization-based design which is an iterative process. In this article, first off, an analytical tool based on the subdomain model is briefly presented. This model is very accurate and much faster than FEM. However, it has high computational time for iterative design and optimization processes.... 

Taking into account X-ray diffraction, one of the well-known methods for calculating the stress-strain of crystals is Williamson-Hall (W–H). The W-H method has three models, namely (1) Uniform deformation model (UDM); (2) Uniform stress deformation model (USDM); and (3) Uniform deformation energy density model (UDEDM). The USDM and UDEDM models are directly related to the modulus of elasticity (E). Young’s modulus is a key parameter in engineering design and materials development. Young’s modulus is considered in USDM and UDEDM models, but in all previous studies, researchers used the average values of Young’s modulus or they calculated Young’s modulus only for a sharp peak of an XRD pattern... 

All costs within the life cycle of a building are known as its life cycle cost (LCC). In the design process of a building, the use of a lower initial cost index to select an option among others with similar performance may not lead to an economically optimal alternative during the life cycle. Hence, today, building designers and investors require a tool to estimate life cycle cost at the conceptual design stage to select an economically efficient option. Resilient solutions generally lead to a higher level of complexity and upfront costs and carry additional embodied environmental impact as well. This study aims to support the design of resilient buildings using a sound LCC methodology in... 

Using control charts to monitor healthcare systems has gained particular attention. In this paper, a risk-adjusted cumulative sum control chart is designed to monitor surgery outputs. Before undergoing surgery, the patients have some unique risk factors which influence the surgery outputs. Thus, risk-adjustment is carried out with the purpose of taking these risks into account using an accelerated failure time model. But the technical implementation of the chart requires determining the design parameters which should be selected in an optimal way putting the desired statistical and economic considerations into service. To this end, a multi-objective model, considering multiple assignable... 

Numerous studies have investigated driving equations used to predict the slip factor in centrifugal compressors so far. Inevitably, through these studies, the ow field characteristics have been simplified and the effects of the related parameters have been neglected. The present study, experimentally and numerically, investigates the slip phenomenon in a specific centrifugal compressor with complex blade curves and splitter blades, considering the main effective parameters such as the number of blades, exit angle, etc. To this end, a three-dimensional simulation of the viscous flow field of the compressor via an appropriate turbulence method was performed. In addition, an experimental study... 

In this study, for the first time, the influence of the nanoporous Zr-based NH2-UiO-66 metal-organic frameworks (MOFs) on the tensile strength and fracture toughness of the epoxy coating was investigated. In addition, the impacts of the UiO particles' functionality (i.e., NH2 or GMA) on the MOFs/epoxy interfacial bonding and nanoparticles dispersion quality in the epoxy resin were examined by the tensile test, dynamic mechanical thermal analysis (DMTA) and field emission-scanning electron microscope (FE-SEM). The NH2-UiO-66 and GMA-UiO-66 MOFs chemical structures were investigated by FT-IR, BET, and FE-SEM approaches. The FE-SEM investigation of the fracture morphology (at the cross-section... 

Mixed-Criticality (MC) systems have recently been devised to address the requirements of real-time systems in industrial applications, where the system runs tasks with different criticality levels on a single platform. In some workloads, a highcritically task might overrun and overload the system, or a fault can occur during the execution. However, these systems must be fault-tolerant and guarantee the correct execution of all highcriticality tasks by their deadlines to avoid catastrophic consequences, in any situation. Furthermore, in these MC systems, the peak power consumption of the system may increase, especially in an overload situation and exceed the processor Thermal Design Power... 

Gamma irradiation systems are used extensively in the industry in order to sterilize medical devices, disinfect hygienic products and increase the shelf life of agricultural products. The method of gamma irradiation is superior to the older methods of heat or chemical treatment because it is by far a simpler operation. In this method, only one parameter, the exposure time is controlled, whereas in the other mentioned methods five or six different parameters need to be controlled. The design of irradiation systems generally includes the size and the location of products, and the arrangement of source rack pencils. In order to optimize the design of the gamma irradiation systems, it is needed... 

The method for modeling switching converters plays a key role in real-time simulators. Associate discrete circuit (ADC) modeling technique is a commonly used method for modeling the switching converter. However, the optimal selection of the ADC-based switch model parameters has great importance in the accuracy of the real-time simulator. In this paper, the design of a real-time simulator for a switching power converter has been done, in which a novel method for detecting optimum values of the switch model parameters has been expressed. Particle swarm optimization (PSO) algorithm is used to find these optimum values using state-space analysis of the modeled circuit in the z-domain. The... 

Additive manufacturing, artificial intelligence and cloud manufacturing are three pillars of the emerging digitized industrial revolution, considered in industry 4.0. The literature shows that in industry 4.0, intelligent cloud based additive manufacturing plays a crucial role. Considering this, few studies have accomplished an integration of the intelligent additive manufacturing and the service oriented manufacturing paradigms. This is due to the lack of prerequisite frameworks to enable this integration. These frameworks should create an autonomous platform for cloud based service composition for additive manufacturing based on customer demands. One of the most important requirements of...