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A rescheduling method for new order arrival is presented based on the concept of dynamic pegging in multi-level production. Upon the arrival of new, unplanned orders, dynamic pegging enables the re-assignment of the Work-In-Progress (WIP) to the existing or newly arrived orders in such a way that the cost of rescheduling is minimized. A simple yet inspiring Mixed Integer Programming (MIP) model is proposed that combines dynamic pegging with rescheduling. The resulting schedules are compared with the ones obtained from two other basic rescheduling approaches. Analysis of the comparisons confirm the superiority of the proposed method in terms of total rescheduling costs. © 2019  

This paper presents a new predictive-reactive rescheduling method for adjusting production schedules in response to the unplanned arrival of new orders in multi-level production. It is based on the concept of dynamic pegging, which enables the reassignment of the Work-In-Progress (WIP) to the existing or newly arrived orders at the time of rescheduling. Extending our previous work on reactive rescheduling with dynamic pegging, the new approach incorporates a probabilistic predictive model of new order arrival in the initial scheduling at the begging of the scheduling horizon. A Mixed Integer Programming (MIP) model is developed for two-phase, predictive-reactive scheduling before and after... 

In this paper a new predictive-reactive rescheduling method is presented based on the dynamic pegging concept. Scheduling adjustments in a multi-level, mixed-model production system are invoked in response to the unplanned events, such as new order arrival, changes in due dates, and order cancellation. By using the dynamic pegging approach at the time of rescheduling, Work-In-Progress (WIP) can be reassigned to the existing or new orders. Based on our previous work on reactive-only rescheduling with dynamic pegging, a Mixed Integer Programming (MIP) model is developed for predictive-reactive scheduling of new orders of different product types that arrive following exponential distribution. A... 

This paper presents the results of an experimental study on the application of strapping technique for retrofit of concrete compressive specimens. In this technique, standard strapping devices, which are used in the packaging industry, are applied to post-tension high strength metal strips around the concrete columns. Experimental program included axial compressive tests on 72 cylindrical and prismatic compressive specimens, which were actively confined by pre-stressed metal strips. The effects of various parameters on strength and ductility of confined concrete were studied including compressive strength of concrete, mechanical volumetric ratio of confining strips, post-tensioning force in... 

This paper presents the results of experimental and analytical study on a new technique of seismic retrofitting of concrete columns. In this technique, standard strapping devices, which are used in the packaging industry, are used to post-tension metal strips around concrete columns. The two ends of the strip are tightened in sealed clamps to maintain the pre-stress force in the strip. Experimental program included axial compressive tests on 30 cylindrical as well as 30 prismatic small-scale columns which were actively confined by pre-stressed metal strips. Longitudinal and lateral strain of concrete and strain in the strips were monitored. Test Results showed significant increase in... 

Ultrasonic waves have been extensively used in many industrial applications including clean devices, pipes and vessels. A clear extension of this usage is the removal of wellbore contaminants by exposing it to high-power ultrasonic waves. In this paper, a mathematical model for ultrasonic propagation through the porous medium around the wellbore is presented. The equations of wave propagation are written in a cylindrical coordinate according to Biot theory and the induced stress in the rock are calculated at each point using finite difference approach Comparison of imposed local stresses with adhesion forces between scales and rock, the properties of ultrasonic transducer, such as frequency... 

Employing an effective rheological model for the flow of drilling fluid that can accurately predict changing conditions is of significant importance in drilling fluid optimization. Traditional generalized Newtonian models cannot predict the time change condition, viscoelastic behavior, role of each component, or microstructural behaviors within the fluid. Consequently, the present research aims to develop constitutive equations in the framework of generalized bracket formalisms and the extra tensor concept that connect the microscopic and macroscopic properties and can overcome the aforementioned problems of traditional rheological models. The developed model is applicable for drilling fluid... 

Intense global competition, dynamic product variations, and rapid technological developments force manufacturing systems to adapt and respond quickly to various changes in the market. Such responsiveness could be achieved through new paradigms such as Reconfigurable manufacturing systems (RMS). In this paper, the problem of configuration design for a scalable reconfigurable RMS that produces different products of a part family is addressed. In order to handle demand fluctuations of products throughout their lifecycles with minimum cost, RMS configurations must change as well. Two different approaches are developed for addressing the system configuration design in different periods. Both... 

Intense global competition, dynamic product variations, and rapid technological developments force manufacturing systems to adapt and respond quickly to various changes in the market. Such responsiveness could be achieved through new paradigms such as Reconfigurable manufacturing systems (RMS). In this paper, the problem of configuration design for a scalable reconfigurable RMS that produces different products of a part family is addressed. In order to handle demand fluctuations of products throughout their lifecycles with minimum cost, RMS configurations must change as well. Two different approaches are developed for addressing the system configuration design in different periods. Both... 

Intense global competition, dynamic product variations, and rapid technological developments force manufacturing systems to adapt and respond quickly to various changes in the market. Such responsiveness could be achieved through new paradigms such as Reconfigurable manufacturing systems (RMS). In this paper, the problem of configuration design for a scalable reconfigurable RMS that produces different products of a part family is addressed. In order to handle demand fluctuations of products throughout their lifecycles with minimum cost, RMS configurations must change as well. Two different approaches are developed for addressing the system configuration design in different periods. Both... 

In Industry 4.0, the emergence of new information technology and advanced manufacturing technology (e.g., digital twin, and robot) promotes the flexibility and smartness of manufacturing systems to deal with production task fluctuation. Digital twin-driven manufacturing system with human-robot collaboration is a typical paradigm of intelligent manufacturing. When production task changes, manufacturing system reconfiguration with dynamic opeartion task allocation between operator (human) and robot is a key manner to maintain the production efficiency of intelligent manufacturing system with human-robot collaboration. However, the differences between operator and robot are neglected during... 

In this paper, the results of recent studies on inelastic seismic response of MDOF shear- building structures are presented. In the last few decades, the concept of response modification factor R has been introduced and developed to account for inelastic nonlinear behaviour of structures under earthquakes. In this paper, an attempt has been made to adjust and extend this concept through introducing a modifying factor Rt This factor is used for dynamic analysis of MDOF structures, including the calculation of inelastic response spectra. Sensitivity analysis was carried out to identify the parameters that have influence on RT- It has been demonstrated that Rt is predominantly a function of... 

In this paper, the results of recent studies on inelastic seismic response of MDOF shear-building structures are presented. In the last few decades, the concept of response modification factor R has been introduced and developed to account for inelastic nonlinear behaviour of structures under earthquakes. In this paper, an attempt has been made to adjust and extend this concept through introducing a modifying factor RT. This factor is used for dynamic analysis of MDOF structures, including the calculation of inelastic response spectra. Sensitivity analysis was carried out to identify the parameters that have influence on RT. It has been demonstratec that RT is predominantly a function of... 

The synthesis of bicyclo[3.3.1]nonane systems is reported. The synthesis is based on the tandem 1,3-dinucleophilic addition of 4-hydroxy-2-quinolinone to quinolinium salts  

Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3), was prepared and fully characterized. The vibrational modes (FT-IR) and NMR data ( 1H and 13C chemical shifts) were compared with the results of Density Functional Theory (DFT) method at the B3LYP/cc-PVTZ level. The calculated vibrational frequencies and NMR chemical shifts are in good agreement with the experimental results. The electronic (UV-Vis) spectrum was calculated using the TD-DFT method in CH2Cl2 with the Polarizable Continuum Model using the integral equation formalism variant (IEFPCM) and was correlated to the experimental spectra. The assignment and analysis of the frontier HOMO and LUMO orbitals indicate that... 

This paper presents the results of an analytical study on the dynamic characteristics of the Shaking Table facilities at Sharif University. This 3 degree of freedom shaking table is driven by 3 servo-control hydraulic actuators, and consists of a 12 ton, 4m×4m×0.6m steel deck. The main objective of this investigation is to identify the degree of flexibility of the deck, and its adverse effects in causing errors in the simulation of seismic effects on different structural specimens. Many frame specimens of different weights and configurations are subjected to seismic motions, and their responses are calculated using FE models. Some of these models were designed to account for eccentric... 

A practical optimization method is applied to design nonlinear truss-like structures subjected to seismic excitation. To achieve minimum weight design, inefficient material is gradually shifted from strong parts to weak parts of a structure until a state of uniform deformation prevails. By considering different truss structures, effects of seismic excitation, target ductility and buckling of the compression members on optimum topology are investigated. It is shown that the proposed method could lead to 60% less structural weight compared to optimization methods based on elastic behavior and equivalent static loads, and is efficient at controlling performance parameters under a design... 

This paper presents analytical part of an investigation on the application of prestressed strips for concrete confinement. In this paper, an analytical model is proposed to predict the compressive stress-strain curve of strapped concrete as a function of the confinement level. The model was calibrated based on the experimental data of compressive tests which were described in part A of this paper. Various parameters are considered in the proposed model including volumetric ratio, yield strength and ultimate strain of confining material, shape of cross section, strength of plain concrete. Three key points were defined on the stress-stress curve of strapped concrete columns and applied in... 

An improved compression algorithm for ECG signals is presented using temporal alignment of beats and 2-D wavelet packet transform (WPT). This 2-D transform based approach utilizes the fact that the electrocardiogram (ECG) signals generally show two types of correlation, namely correlation between subsequent samples within each ECG cycle (intrabeat) and correlation between subsequent cycles (interbeat). One simple compression algorithm in the 2-D WPT domain, which is applied to some records in the MIT-BIH arrhythmia database shows lower percent root mean square difference (PRD) than 1-D wavelet based compression methods for the same compression ratio (CR). © 2001 IEEE  

This paper presents a simulation-based study of the delay fault testing in CMOS logic circuits. A novel built-in self-test (BIST) technique is presented for detecting delay faults in this logic family. This scheme does not need test-pattern generation, and thus can be used for robust on-line testing. Simulation results for area, delay, and power overheads are presented. © 2007 IEEE