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integer-linear-programming
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Pave the way for sustainable smart homes: A reliable hybrid AC/DC electricity infrastructure
, Article Electric Power Systems Research ; Volume 210 , 2022 ; 03787796 (ISSN) ; Vahidinasab, V ; Safdarian, A ; Shafie khah, M ; Catalão, J. P. S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The development of emerging smart grid technologies has led to more and more penetration of renewable energy resources and electric energy storage in the residential sectors. Besides, owing to the significant evolution of power electronic devices, there is a rapid growth in penetration of DC loads and generations, such as PV and electric vehicles (EVs), into the buildings and homes as a building block of the future smart cities. This is despite the fact that the electricity infrastructure of the conventional buildings is designed based on AC electricity and as a result, there would be a lot of losses due to the frequent power conversion from AC to DC and vice versa. Besides, according to a...
The utilization of patients’ information to improve the performance of radiotherapy centers: A data-driven approach
, Article Computers and Industrial Engineering ; Volume 172 , 2022 ; 03608352 (ISSN) ; Najafi, M ; Mesgari, S ; Zolfagharinia, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The high demand for radiotherapy services, combined with the limited capacity of available resources, patient unpunctuality, and series of appointments, makes Patient Appointment Scheduling (PAS) in radiotherapy centers very challenging. Although most centers use a First-Come-First-Serve (FCFS) policy for appointment scheduling, this approach does not consider patients’ behaviors, and consequently, it performs poorly. This type of inappropriate scheduling usually leads to inefficiency at the center and/or patient dissatisfaction. This study provides a data-driven approach to patient appointment scheduling to deal with the challenges mentioned above, and it considers patients’ histories of...
MASTER: Reclamation of hybrid scratchpad memory to maximize energy saving in multi-core edge systems
, Article IEEE Transactions on Sustainable Computing ; Volume 7, Issue 4 , 2022 , Pages 749-760 ; 23773782 (ISSN) ; Hoseinghorban, A ; Bazzaz, M ; Salehi, M ; Ejlali, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Most modern multi-core edge devices work in outdoor situations with limited power supplies like energy harvester and batteries. Therefore, energy consumption is a fundamental issue in which the memory subsystem has a significant role. Scratchpad memories (SPM) can provide a broad potential for energy saving. Still, due to the insufficient SPM capacity in such edge devices, a rigorous SPM data allocation scheme is necessary to reduce the energy consumption of the memory subsystem. Emerging non-volatile memories (NVMs) are very useful to reduce the energy consumption of the memory subsystem. Compared with SRAM, NVMs have lower leakage power and higher density, but the read and write latencies...
On the explicit formulation of reliability assessment of distribution systems with unknown network topology: Incorporation of DG, switching interruptions, and customer-interruption quantification
, Article Applied Energy ; Volume 324 , 2022 ; 03062619 (ISSN) ; Lehtonen, M ; Fotuhi Firuzabad, M ; Muñoz Delgado, G ; Contreras, J ; Arroyo, J. M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This paper presents an original approach for the evaluation of reliability of active distribution networks with unknown topology. Built upon novel reformulations of conventional definitions for distribution reliability indices, the dependence of system-oriented reliability metrics on network topology is explicitly formulated using a set of mixed-integer linear expressions. Unlike previously reported works also modeling mathematically the relationship between reliability assessment and network topology, the proposed approach allows considering the impact of distributed generation (DG) while accounting for switching interruptions. Moreover, for the first time in the emerging closely related...
Tie-line planning for resilience enhancement in unbalanced distribution networks
, Article IET Generation, Transmission and Distribution ; Volume 16, Issue 5 , 2022 , Pages 1030-1046 ; 17518687 (ISSN) ; Safdarian, A ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
Over the past decades, there has been a dramatic increase in the frequency of natural disasters, which are the leading causes of large-scale power outages. This paper, therefore, assesses the significance and role of optimal tie-line construction in improving the service restoration performance of unbalanced power distribution systems in the aftermath of high-impact low-probability incidents. In doing so, a restoration process aware stochastic mixed-integer linear programming model is developed to find the optimal locations for new tie-line construction in unbalanced three-phase distribution systems. In particular, the restoration process of distribution systems, including the fault...
Reliability-Based optimal bidding strategy of a technical virtual power plant
, Article IEEE Systems Journal ; Volume 16, Issue 1 , 2022 , Pages 1080-1091 ; 19328184 (ISSN) ; Fotuhi Firuzabad, M ; Kabirifar, M ; Moeini Aghtaie, M ; Lehtonen, M ; Wang, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Technical virtual power plant (TVPP) aggregates distributed energy resources in order to trade in wholesale electricity market while taking operational constraints of network into account and offering services to distribution system operator. This article presents a new framework to incorporate the reliability of distribution network into designing the optimal bidding strategy of a TVPP in day-ahead energy market. In the proposed framework, the TVPP determines the multisteps biddings as pairs of power and price aiming at maximizing its profit in market while minimizing the outage costs due to contingency occurrences. The model is formulated as a bilevel optimization problem in which the...
Single machine scheduling problem with batch outsourcing
, Article International Journal of Engineering, Transactions B: Applications ; Volume 35, Issue 5 , 2022 , Pages 1006-1016 ; 1728144X (ISSN) ; Kianfar, F ; Sharif University of Technology
Materials and Energy Research Center
2022
Abstract
Outsourcing as a useful strategy in the industry can be integrated into scheduling problems. Moreover, batch outsourcing is a practical assumption owing to the logistics issues for transferring the parts between the manufacturer and the subcontractors. However, this assumption is rarely addressed in the scheduling literature. In this paper, a novel single machine scheduling problem with the option of batch outsourcing is studied. The objective is to minimize the sum of the total completion time of the jobs and the total outsourcing cost. To solve the problem, first, two mixed-integer linear programming (MILP) models, named MP1 and MP2, are developed, which respectively use a straightforward...
A stochastic framework for optimal island formation during two-phase natural disasters
, Article IEEE Systems Journal ; Volume 16, Issue 2 , 2022 , Pages 2090-2101 ; 19328184 (ISSN) ; Vakilian, M ; Farzin, H ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
This article proposes a new three-stage stochastic framework for dealing with predictable two-phase natural disasters in distribution systems. This framework is a multiobjective optimization, in which the amount of curtailed energy, the number of switching actions, and the vulnerability of operational components are selected as the main criteria for decision-making process. The optimization problem is formulated in the form of a stochastic mixed-integer linear programming (MILP) problem. In this article, a windstorm event followed by flooding is analyzed as a two-phase natural disaster. In this regard, the uncertainties associated with gust-wind speed, floodwater depths, and load demands are...
Optimal equilibrium selection of price-maker agents in performance-based regulation market
, Article Journal of Modern Power Systems and Clean Energy ; Volume 10, Issue 1 , 2022 , Pages 204-212 ; 21965625 (ISSN) ; Sheikhi, A ; Ranjbar, A. M ; Sun, W ; Sharif University of Technology
State Grid Electric Power Research Institute Nanjing Branch
2022
Abstract
This paper analyzes the oligopolistic equilibria of multiple price-maker agents in performance-based regulation (PBR) markets. In these markets, there are price-maker agents representing some frequency regulation (FR) providers and a number of independent price-taker FR providers. A model of equilibrium problem with equilibrium constraints (EPECs) is employed in this paper to study the equilibria of a PBR market in the presence of price-maker agents and price-taker FR providers. Due to the incorporation of the FR providers' dynamics, the proposed model is reformulated as a mixed-integer linear programming (MILP) problem over innovative mathematical techniques. An optimal equilibrium point is...
An enhanced MILP model for multistage reliability-constrained distribution network expansion planning
, Article IEEE Transactions on Power Systems ; Volume 37, Issue 1 , 2022 , Pages 118-131 ; 08858950 (ISSN) ; Abbaspour, A ; Fotuhi Firuzabad, M ; Muñoz Delgado, G ; Contreras, J ; Lehtonen, M ; Arroyo, J. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Reliability is an essential factor in distribution networkt expansion planning. However, standard distribution reliability assessment techniques rely on quantifying the impact of a pre-specified set of events on service continuity through the simulation of component outages, one at a time. Due to such a simulation-based nature, the incorporation of reliability into distribution network expansion planning has customarily required the application of heuristic and metaheuristic approaches. Recently, alternative mixed-integer linear programming (MILP) models have been proposed for distribution network expansion planning considering reliability. Nonetheless, such models suffer from either low...
Mixed integer linear programming problem for personnel multi-day shift scheduling: A case study in an Iran hospital
, Article Alexandria Engineering Journal ; Volume 61, Issue 1 , 2022 , Pages 419-426 ; 11100168 (ISSN) ; Sharifnia, S. M. E ; Cárdenas Barrón, L. E ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The application of mathematical and systematic models and approaches to health is on the rise. In this study, a mixed-integer linear programming problem with cost (staff payroll) objective function is proposed to determine homogeneous personnel shift scheduling so that the constraints of the number of personnel per shift are met. The purpose of this study is to optimize the scheduling of personnel with the same skills to minimize variable hospital costs. In a hospital, homogeneous personnel might be skilled nurses who can work in the same departments or service staff of the departments. First, a mathematical model is proposed for scheduling as a linear problem and solved using Lingo...
A linearized transmission expansion planning model under N − 1 criterion for enhancing grid-scale system flexibility via compressed air energy storage integration
, Article IET Generation, Transmission and Distribution ; Volume 16, Issue 2 , 2022 , Pages 208-218 ; 17518687 (ISSN) ; Moeini Aghtaie, M ; Fotuhi Firuzabad, M ; Dehghanian, P ; Khoshjahan, M ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
The concept of flexibility is defined as the power systems’ ability to effectively respond to changes in power generation and demand profiles to maintain the supply–demand balance. However, the inherent flexibility margins required for successful operation have been recently challenged by the unprecedented arrival of uncertainties, driven by constantly changing demand, failure of conventional units, and the intermittent outputs of renewable energy sources (RES). Tackling these challenges, energy storage systems (ESS) as one important player of the new power grids can enhance the system flexibility. It, therefore, calls for an efficient planning procedure to ensure flexibility margins by...
PVMC: Task mapping and scheduling under process variation heterogeneity in mixed-criticality systems
, Article IEEE Transactions on Emerging Topics in Computing ; Volume 10, Issue 2 , 2022 , Pages 1166-1177 ; 21686750 (ISSN) ; Ranjbar, B ; Rohbani, N ; Ejlali, A ; Sharif University of Technology
IEEE Computer Society
2022
Abstract
Embedded Systems (ESs) have migrated from special-purpose hardware to commodity hardware. These systems have also tended to Mixed-Criticality (MC) implementations, executing applications of different criticalities upon a shared platform. Multi-cores, which are commonly used to design MC Systems (MCSs), bring out new challenges due to the Process Variation (PV). Power and frequency asymmetry affects the predictability of ESs. In this work, variation-aware techniques are explored to not only improve the reliability of MCSs, but also aid the scheduling and energy saving of them. We leverage the Core-to-Core (C2C) variations to protect high-criticality tasks and provide full service for a high...
A comprehensive framework for sustainable closed-loop supply chain network design
, Article Journal of Cleaner Production ; Volume 332 , 2022 ; 09596526 (ISSN) ; Kian, H ; Nasr, A.K ; Govindan, K ; Mina, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Many companies face challenges in reducing their supply chain costs while increasing sustainability and customer service levels. A comprehensive framework for a sustainable closed-loop supply chain (CLSC) network is a practical solution to these challenges. Hence, for the first time, this study considers an integrated multi-objective mixed-integer linear programming (MOMILP) model to design sustainable CLSC networks with cross-docking, location-inventory-routing, time window, supplier selection, order allocation, transportation modes with simultaneous pickup, and delivery under uncertainty. An intelligent simulation algorithm is proposed to produce CLSC network data with probabilistic...
Latency-aware service provisioning in survivable multilayer IP-over-elastic optical networks to support multi-class of service transmission
, Article Computer Communications ; Volume 183 , 2022 , Pages 161-170 ; 01403664 (ISSN) ; Beyranvand, H ; Salehi, J. A ; Sharif University of Technology
Elsevier B.V
2022
Abstract
To meet the requirements of the emerging applications, future networks must transmit multiple class of services traffic with diverse quality of service (QoS) requirements. In this paper, we formulate an integer linear programming (ILP) to design multilayer internet protocol (IP) over elastic optical networks (EONs), IP-over-EONs to support multi-class services with different latency and availability requirements. The objective of the ILP is to minimize capital expenditure (CAPEX) and spectrum usage while satisfying all QoS constraints in terms of latency and survivability mechanism. Furthermore, a heuristic algorithm is proposed to solve this problem in large-scale networks. We compare the...
PVMC: task mapping and scheduling under process variation heterogeneity in mixed-criticality systems
, Article IEEE Transactions on Emerging Topics in Computing ; 2021 ; 21686750 (ISSN) ; Ranjbar, B ; Rohbani, N ; Ejlali, A. R ; Sharif University of Technology
IEEE Computer Society
2021
Abstract
Embedded systems have migrated from special-purpose hardware to commodity hardware. These systems have also tended to Mixed-Criticality (MC) implementations, executing applications of different criticalities upon a shared platform. Multi-core processors, which are commonly used to design MC systems, bring out new challenges due to the process variations. Power and frequency asymmetry affects the predictability of embedded systems. In this work, variation-aware techniques are explored to not only improve the reliability of MC systems, but also aid the scheduling and energy saving of them. We leverage the core-to-core (C2C) variations to protect high-criticality tasks and provide full service...
Multi-step island formation and repair dispatch reinforced by mutual assistance after natural disasters
, Article International Journal of Electrical Power and Energy Systems ; Volume 126 , 2021 ; 01420615 (ISSN) ; Vakilian, M ; Farzin, H ; Lehtonen, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Extreme weather events can devastate parts of power grids. Thus, the appropriate post-disaster reaction is a crucial duty for power utilities. To address this important concern, a new two-stage framework is proposed in this paper. Stage I optimally coordinates disaster mutual assistance between affected and supporting utilities. To this end, distance between the damaged and supporting utilities, extent of damage, and repair resources are taken into consideration as decision criteria. Then, a novel formulation in the form of mixed integer linear programming (MILP) is developed for mutual aid management problem. The results of stage I are used as inputs to stage II. A new multi-horizon...
A stochastic framework for optimal island formation during two-phase natural disasters
, Article IEEE Systems Journal ; 2021 ; 19328184 (ISSN) ; Vakilian, M ; Farzin, H ; Lehtonen, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
This article proposes a new three-stage stochastic framework for dealing with predictable two-phase natural disasters in distribution systems. This framework is a multiobjective optimization, in which the amount of curtailed energy, the number of switching actions, and the vulnerability of operational components are selected as the main criteria for decision-making process. The optimization problem is formulated in the form of a stochastic mixed-integer linear programming (MILP) problem. In this article, a windstorm event followed by flooding is analyzed as a two-phase natural disaster. In this regard, the uncertainties associated with gust-wind speed, floodwater depths, and load demands are...
A fuzzy solution approach to supplier selection and order allocation in green supply chain considering the location-routing problem
, Article Scientia Iranica ; Volume 28, Issue 1 E , 2021 , Pages 446-464 ; 10263098 (ISSN) ; Haji, A ; Mina, H ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
In the eld of supply chain, selecting a suitable green supplier could signi cantly help us decrease the cost and risks of the operations and increase the quality of green supply. This paper develops an integrated two-stage approach based on Fuzzy Analytic Hierarchy Process (FAHP) and multi-objective mixed-integer linear programming to select suppliers and allocate order in the green supply chain. In the rst stage, suppliers are evaluated using FAHP method and in the second stage, a multi-product multi-period supply chain is developed considering green location-routing problem, discounting, and time window under uncertainty. Then, a fuzzy solution approach is applied to solve the proposed...
Developing a market-oriented approach for supplying flexibility ramping products in a multimicrogrid distribution system
, Article IEEE Transactions on Industrial Informatics ; Volume 17, Issue 10 , 2021 , Pages 6765-6775 ; 15513203 (ISSN) ; Salehi, J ; Moeini Aghtaie, M ; Sharif University of Technology
IEEE Computer Society
2021
Abstract
Rapid growth of the variable and intermittent renewable generation in multimicrogrid distribution network (MMG-DN) has derived a gross violation in power balance due to the scarcity of ramp capacity. To neutralize this shortage, the present study develops a market-oriented approach for supplying flexibility ramping products (FRPs) in an MMG-DN. In this article, the proposed approach appraises a ramping capacity of local microgrids (MGs), which encompass various distributed energy resources through a bilevel programming. To do so, an interval-based security constraint economic dispatch process is accomplished at the upper level considering the network's requirement of upward/downward ramp...