The load-carrying capacity of an eccentrically loaded reinforced concrete column affected by corr... more The load-carrying capacity of an eccentrically loaded reinforced concrete column affected by corrosion of reinforcement will progressively decrease with time due to the buildup of corrosion-induced damage in the form of loss of reinforcement area, cracking and spalling of concrete cover. Due to the complexity of corrosion problems, a probability-based assessment of failure, instead of a deterministic approach to ascertain safety, is prudently more appealing. An attempt has been made to propose a method for computing probability of failure of corroded eccentrically loaded columns using Monte Carlo simulation (MCS) of a proposed limit state safety function based on a time-dependent strength prediction model for the residual strength. The MCS covers a large number of possible combinations of all governing parameters related to strength within their prescribed distributional characteristics. The results show that MCS can be used to estimate probabilities of failure, and that the corrosion current density and the ratio of eccentricity of the applied axial load to the depth of the section, e/h, are the two significant factors that affect the probability of failure at a prescribed corrosion period the most.
The global COVID-19 pandemic forced the construction industry to a standstill. In the wake of the... more The global COVID-19 pandemic forced the construction industry to a standstill. In the wake of the pandemic, this sector must be prepared to make bold, innovative moves to prepare for the future. Over the past few years, the use of drones and robotics has expanded with many commercial uses, including in the construction industry. Drone-driven automation has an enormous impact in improving productivity and reducing cost and schedule overruns. The use of drones, along with the application of Internet of Things (IoT) and robotics, can make a significant impact on the supply chain and improve inventory accuracy, leading to faster and more cost-effective building projects. This paper will propose and statistically substantiate an optimization model for supply chain management through the accelerated use of drones and Artificial Intelligence (AI) in the post-pandemic era. The use of smart devices and IoT will allow warehouse managers to have real-time visibility of the location and invento...
This paper presents a generalized targeting model that subsumes most known targeting problems. In... more This paper presents a generalized targeting model that subsumes most known targeting problems. In this paper, a recurrent state is defined as a condition that requires reprocessing or rework. The generalized model can accommodate one or two specifications limits and can be used for the following quality characteristics: The nominal-the-better, the larger-the-better, and the smaller-the-better. This model can be used to find the optimal mean of a quality characteristic, as well as the optimal specification limits. In addition, the paper studies the conditions under which the solution to the proposed model can provide a global solution. The paper shows that, for some of the special cases and under very general conditions, the optimal lower limit should be zero and the optimal upper limit should be infinity. This paper proves that the expected profits improve for the case where only a lower limit on the quality characteristic is used, if a recurrent state is included by adding an optim...
We consider the queueing system denoted by M/MN/1/N where customers are served in batches of maxi... more We consider the queueing system denoted by M/MN/1/N where customers are served in batches of maximum size N. The model is motivated by a traffic application. The time-dependent probability distribution for the number of customers in the system is obtained in closed form. The solution is used to predict the optimal service rates during a finite time horizon.
Due to increase in environmental concerns along with stringent government legislations, forcing i... more Due to increase in environmental concerns along with stringent government legislations, forcing industry practitioners and policy makers to tak e a fresh look at the impact of their supply chain activities on the environment. Various carbon regulatory mechanisms have been proposed by governmental agencies around the globe, which aims to curb the carbon emission. In this paper, optimization models based on carbon regulatory policies for a closed-loop supply chain design and logistics operations are p resented. Specifically, the following three common regulatory policies are considered: strict carbon caps, carbon tax, and carbon cap-and-trade. The proposed models optimize not only costs but also em issions in the supply chain operations. The models capture: the trade-o�° s that exist between location and transportation modes d ecisions; and the trade-o�° s between costs and emissions in the supply chain operations. Numerical experiment illustrates different policies and th eir impact ...
... Problem (3) can also be viewed as a nonlinear programming problem, where techniques like the ... more ... Problem (3) can also be viewed as a nonlinear programming problem, where techniques like the KKT (Karush-Khun-Tucker) with Lagragian multipliers [14] may ... the problem of finding the distance between a disk Ki lying in the (Xo,Yo) plane and centered at the origin Oo of the ...
Climate change attributed by greenhouse gas emissions have triggered some countries to implement ... more Climate change attributed by greenhouse gas emissions have triggered some countries to implement various carbon regulatory mechanisms to curb and regulate industrial carbon emissions. To be effective, the industry environmental footprint needs to address holistically via closed-loop supply chains (CLSC). This research proposes an optimization approach to address CLSC design problem with carbon footprint considerations. It integrates the carbon emission policies into supply chain’s strategic, tactical and operational selection decisions. A robust counterpart of the proposed model is developed based on three alternative uncertainty sets. The model extends further to investigate the impact of the three commonly practiced carbon regulatory policies including carbon cap, carbon tax, and carbon cap-and-trade on the supply chain strategic and operational decisions. Numerical results indicate that carbon cap-and-trade policy is the most flexible and efficient policy as compared to carbon ca...
The load-carrying capacity of an eccentrically loaded reinforced concrete column affected by corr... more The load-carrying capacity of an eccentrically loaded reinforced concrete column affected by corrosion of reinforcement will progressively decrease with time due to the buildup of corrosion-induced damage in the form of loss of reinforcement area, cracking and spalling of concrete cover. Due to the complexity of corrosion problems, a probability-based assessment of failure, instead of a deterministic approach to ascertain safety, is prudently more appealing. An attempt has been made to propose a method for computing probability of failure of corroded eccentrically loaded columns using Monte Carlo simulation (MCS) of a proposed limit state safety function based on a time-dependent strength prediction model for the residual strength. The MCS covers a large number of possible combinations of all governing parameters related to strength within their prescribed distributional characteristics. The results show that MCS can be used to estimate probabilities of failure, and that the corrosion current density and the ratio of eccentricity of the applied axial load to the depth of the section, e/h, are the two significant factors that affect the probability of failure at a prescribed corrosion period the most.
The global COVID-19 pandemic forced the construction industry to a standstill. In the wake of the... more The global COVID-19 pandemic forced the construction industry to a standstill. In the wake of the pandemic, this sector must be prepared to make bold, innovative moves to prepare for the future. Over the past few years, the use of drones and robotics has expanded with many commercial uses, including in the construction industry. Drone-driven automation has an enormous impact in improving productivity and reducing cost and schedule overruns. The use of drones, along with the application of Internet of Things (IoT) and robotics, can make a significant impact on the supply chain and improve inventory accuracy, leading to faster and more cost-effective building projects. This paper will propose and statistically substantiate an optimization model for supply chain management through the accelerated use of drones and Artificial Intelligence (AI) in the post-pandemic era. The use of smart devices and IoT will allow warehouse managers to have real-time visibility of the location and invento...
This paper presents a generalized targeting model that subsumes most known targeting problems. In... more This paper presents a generalized targeting model that subsumes most known targeting problems. In this paper, a recurrent state is defined as a condition that requires reprocessing or rework. The generalized model can accommodate one or two specifications limits and can be used for the following quality characteristics: The nominal-the-better, the larger-the-better, and the smaller-the-better. This model can be used to find the optimal mean of a quality characteristic, as well as the optimal specification limits. In addition, the paper studies the conditions under which the solution to the proposed model can provide a global solution. The paper shows that, for some of the special cases and under very general conditions, the optimal lower limit should be zero and the optimal upper limit should be infinity. This paper proves that the expected profits improve for the case where only a lower limit on the quality characteristic is used, if a recurrent state is included by adding an optim...
We consider the queueing system denoted by M/MN/1/N where customers are served in batches of maxi... more We consider the queueing system denoted by M/MN/1/N where customers are served in batches of maximum size N. The model is motivated by a traffic application. The time-dependent probability distribution for the number of customers in the system is obtained in closed form. The solution is used to predict the optimal service rates during a finite time horizon.
Due to increase in environmental concerns along with stringent government legislations, forcing i... more Due to increase in environmental concerns along with stringent government legislations, forcing industry practitioners and policy makers to tak e a fresh look at the impact of their supply chain activities on the environment. Various carbon regulatory mechanisms have been proposed by governmental agencies around the globe, which aims to curb the carbon emission. In this paper, optimization models based on carbon regulatory policies for a closed-loop supply chain design and logistics operations are p resented. Specifically, the following three common regulatory policies are considered: strict carbon caps, carbon tax, and carbon cap-and-trade. The proposed models optimize not only costs but also em issions in the supply chain operations. The models capture: the trade-o�° s that exist between location and transportation modes d ecisions; and the trade-o�° s between costs and emissions in the supply chain operations. Numerical experiment illustrates different policies and th eir impact ...
... Problem (3) can also be viewed as a nonlinear programming problem, where techniques like the ... more ... Problem (3) can also be viewed as a nonlinear programming problem, where techniques like the KKT (Karush-Khun-Tucker) with Lagragian multipliers [14] may ... the problem of finding the distance between a disk Ki lying in the (Xo,Yo) plane and centered at the origin Oo of the ...
Climate change attributed by greenhouse gas emissions have triggered some countries to implement ... more Climate change attributed by greenhouse gas emissions have triggered some countries to implement various carbon regulatory mechanisms to curb and regulate industrial carbon emissions. To be effective, the industry environmental footprint needs to address holistically via closed-loop supply chains (CLSC). This research proposes an optimization approach to address CLSC design problem with carbon footprint considerations. It integrates the carbon emission policies into supply chain’s strategic, tactical and operational selection decisions. A robust counterpart of the proposed model is developed based on three alternative uncertainty sets. The model extends further to investigate the impact of the three commonly practiced carbon regulatory policies including carbon cap, carbon tax, and carbon cap-and-trade on the supply chain strategic and operational decisions. Numerical results indicate that carbon cap-and-trade policy is the most flexible and efficient policy as compared to carbon ca...
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Papers by Shokri Selim