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A model for stochastic planning of distribution network and autonomous DG units
, Article IEEE Transactions on Industrial Informatics ; Volume 16, Issue 6 , August , 2020 , Pages 3685-3696 ; Farzin, H ; Abbaspour, A ; Fotuhi-Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
IEEE Computer Society
2020
Abstract
This article presents a mixed-integer linear stochastic model for the optimal expansion planning of electricity distribution networks and distributed generation (DG) units. In the proposed framework, autonomous DG units are aggregated and modeled using the well-known energy hub concept. In this model, the uncertainties of heat and electricity demand as well as renewable generation are represented using various scenarios. Although this is a standard technique to capture the uncertainties, it drastically increases the dimensions of this optimization problem and makes it practically intractable. In order to address this issue, a novel iterative method is developed in this article to enhance the...
3RSeT: Read disturbance rate reduction in STT-mram caches by selective tag comparison
, Article IEEE Transactions on Computers ; 2021 ; 00189340 (ISSN) ; Farbeh, H ; Asadi, H ; Sharif University of Technology
IEEE Computer Society
2021
Abstract
Recent development in memory technologies has introduced Spin-Transfer Torque Magnetic RAM (STT-MRAM) as the most promising replacement for SRAMs in on-chip cache memories. Besides its lower leakage power, higher density, immunity to radiation-induced particles, and non-volatility, an unintentional bit flip during read operation, referred to as read disturbance error, is a severe reliability challenge in STT-MRAM caches. One major source of read disturbance error in STT-MRAM caches is simultaneous accesses to all tags for parallel comparison operation in a cache set, which has not been addressed in previous work. This paper first demonstrates that high read accesses to tag arrays extremely...
3RSeT: Read disturbance rate reduction in STT-MRAM caches by selective tag comparison
, Article IEEE Transactions on Computers ; Volume 71, Issue 6 , 2022 , Pages 1305-1319 ; 00189340 (ISSN) ; Farbeh, H ; Asadi, H ; Sharif University of Technology
IEEE Computer Society
2022
Abstract
Recent development in memory technologies has introduced Spin-Transfer Torque Magnetic RAM (STT-MRAM) as the most promising replacement for SRAMs in on-chip cache memories. Besides its lower leakage power, higher density, immunity to radiation-induced particles, and non-volatility, an unintentional bit flip during read operation, referred to as read disturbance error, is a severe reliability challenge in STT-MRAM caches. One major source of read disturbance error in STT-MRAM caches is simultaneous accesses to all tags for parallel comparison operation in a cache set, which has not been addressed in previous work. This article first demonstrates that high read accesses to tag array extremely...
A novel PSO (Particle Swarm Optimization)-based approach for optimal schedule of refrigerators using experimental models
, Article Energy ; Volume 107 , 2016 , Pages 707-715 ; 03605442 (ISSN) ; Ranjbar, H ; Hatami, A ; Iman Eini, H ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
Refrigerators have considerable share of residential consumption. They can be, however, flexible loads because their operating time and consumption patterns can be changed to some extent. Accordingly, they can be selected as a target for the study of Demand Side Management plans. In this paper, two experimental models for a refrigerator are derived. In obtaining the first model, following assumptions are made: the ambient temperature of refrigerator is assumed to be constant and the refrigerator door is remained closed. However, in the second model the variation of ambient temperature and door-opening effects are considered according to some general patterns. Further, two strategies are...
Profit-based unit commitment of integrated CHP-thermal-heat only units in energy and spinning reserve markets with considerations for environmental CO2 emission cost and valve-point effects
, Article Energy ; Volume 133 , 2017 , Pages 621-635 ; 03605442 (ISSN) ; Ardehali, M. M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
For the purposes of lowering environmental emission cost and increasing economic profit, energy efficient combined heat and power (CHP) units can be integrated with conventional separate heat and power production units to meet heat and power demands. The goal of this study is to develop and examine a novel heuristic and deterministic optimization algorithm for solving the profit-based unit commitment (PBUC) problem for a generation company with integrated CHP-thermal-heat only system for (i) satisfying demands for heat and power, (ii) selling spinning reserve for power, (iii) reducing environmental CO2 emission cost, and (iv) accounting for valve-point effects for steam turbines. For...
Annual comparative performance and cost analysis of high temperature, sensible thermal energy storage systems integrated with a concentrated solar power plant
, Article Solar Energy ; Volume 153 , 2017 , Pages 153-172 ; 0038092X (ISSN) ; Taylor, R. A ; Nithyanandam, K ; Shafiei Ghazani, A ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
The present study conducts a comprehensive comparative techno-economic analysis of some near-term sensible thermal energy storage (TES) alternatives to the ‘standard’ two-tank molten salt system for concentrated solar power (CSP) plants. As such, we conducted detailed, relative annual transient simulations for single-medium thermocline (SMT), dual-media thermocline (DMT), and shell-and-tube (ST) systems. To be consistent with recent literature, the DMT and ST systems use concrete with a porosity of 0.2 (e.g. where concrete occupies 80% of the system) as their low cost filler material. The systems were integrated into a validated 19.9 MWe Gemasolar CSP model, which has a solar multiple of...
Extended opportunity cost model to find near equilibrium electricity prices under non-convexities
, Article Applied Energy ; Volume 240 , 2019 , Pages 251-264 ; 03062619 (ISSN) ; Pirnia, M ; Fuller, J. D ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This paper finds near equilibrium prices for electricity markets with non-convexities due to binary variables, in order to reduce the market participants’ opportunity costs, such as generators’ unrecovered costs. The opportunity cost is defined as the difference between the profit when the instructions of the market operator are followed and when the market participants can freely make their own decisions based on the market prices. We use the minimum complementarity approximation to the minimum total opportunity cost model, from previous research, with tests on a much more realistic unit commitment model than in previous research, including features such as reserve requirements, ramping...
Energy, exergy, exergoeconomics, and exergoenvironmental assessment of three brine recycle humidification-dehumidification desalination systems applicable for industrial wastewater treatment
, Article Energy Conversion and Management ; Volume 205 , 2020 ; Moosavi, A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Using zero liquid discharge systems is one of the efficient methods to reduce the negative environmental impact of the brines of the desalination systems and also to recycle the industrial wastewaters for reuse. Due to the simple fabrication process, low maintenance cost, intensive to inlet water quality, and the ability to use renewable and low-grade-heat, modified humidification-dehumidification systems may be a proper choice for the zero liquid discharge applications. Thus, in the present study, the energy, exergy, exergoeconomic, and exergoenvironmental assessment of three advanced brine recycle humidification-dehumidification systems for zero liquid discharge operation are...
A cyber-physical system for building automation and control based on a distributed MPC with an efficient method for communication
, Article European Journal of Control ; Volume 61 , 2021 , Pages 151-170 ; 09473580 (ISSN) ; Farhadi, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This paper introduces a cyber-physical system for building automation and control that is developed based on a distributed model predictive control. The implemented distributed method significantly reduces computation overhead with respect to the centralized methods. However, continuous data transfer between subsystems, which are often far from each other, is required when using this method. Information transmission between subsystems is very often subject to the limitations of transmission bandwidth and/or short communication range resulting in significant communication overhead. This causes significant time latency between making measurements and applying control commands, which adversely...
A new designed linear Fresnel lens solar concentrator based on spectral splitting for passive cooling of solar cells
, Article Energy Conversion and Management ; Volume 230 , 2021 ; 01968904 (ISSN) ; Saboohi, Y ; Moshfegh, A. Z ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The use of solar concentrators can be an alternative for initial cost reduction in the PV systems. However, they suffer from high cell temperature that can be overcome by different active or passive cooling approaches. Spectral splitting and the elimination of high-energy solar photons are effective solutions for cell temperature reduction. In this study, we developed a Polymethyl methacrylate Spectral Splitting Fresnel Lens (SSFL) for linear concentration using a new design, which directs the desired portion of the spectrum towards the cell and diffracts the rest to eliminate the use of beam splitters or nanofluids in the spectral splitting system. Different SSFLs were considered for...
Predicting the environmental economic dispatch problem for reducing waste nonrenewable materials via an innovative constraint multi-objective Chimp Optimization Algorithm
, Article Journal of Cleaner Production ; Volume 365 , 2022 ; 09596526 (ISSN) ; Ren, H ; Habibi, M ; Mohammed, K. J ; Khadimallah, M. A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The usage of conventional fossil fuels has aided fast economic growth while also having negative consequences, such as increased global warming and the destruction of the ecosystem. This paper proposes a novel swarm-based metaheuristic method called Chimp Optimization Algorithm (ChOA) to tackle the environmental, economic dispatch issue and reducing the waste nonrenewable materials. In this regard, two objective functions named fuel cost function and emission cost function are proposed. Unique constrained handling also solves the challenge of multi-objective optimization. Standard IEEE 30 bus with six generators and a 10-unit system are used to demonstrate the usefulness of ChOA. The result...
Peer-to-Peer energy sharing among smart energy hubs in an integrated heat-electricity network
, Article Electric Power Systems Research ; Volume 206 , 2022 ; 03787796 (ISSN) ; Sheikhi, A ; Ashouri Zadeh, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
By increasing the penetration level of the combined heat and power systems and demand response programs between energy consumers in the distribution network, the interaction between electricity and the natural gas network becomes more complicated. This paper proposes a peer-to-peer (P2P) energy sharing scheme for energy trading among Smart Energy Hubs (S.E. Hubs) which can trade both electrical and thermal energy with each other to reduce their cost and, reduce their dependency to gas and electricity utility companies. A two-stage energy strategy is presented. In the first stage, the S.E. Hubs total social cost is reduced by finding the optimal energy sharing profiles. And, in the second...
Operational strategy optimization of a hybrid green power system based on fuzzy logic controller with considering for optimal sizing and analysis of different priorities for energy storage
, Article Sustainable Energy, Grids and Networks ; Volume 32 , 2022 ; 23524677 (ISSN) ; Moeini Aghtaie, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Renewable energy (RE) as a new player in the generation sector of power systems imposes new challenges to the system operators. The intermittent nature of REs for systems where are autonomous calls for new operational and planning strategies to reach more efficient power management. An autonomous hybrid green power system (HGPS) should be able to meet the load while keeping the cost of the HGPS as low as possible. Many studies have presented different un-optimal and optimal operational strategies, a few of which were optimally sized. In this regard, this paper develops a new thorough framework for designing and optimizing an autonomous HGPS. To reach this goal, the proposed model (a)...
Localized conditional source-term estimation model for turbulent combustion
, Article Combustion and Flame ; Volume 235 , 2022 ; 00102180 (ISSN) ; Salehi, M. M ; Sharif University of Technology
Elsevier Inc
2022
Abstract
A novel functional form for approximating the conditional scalars in turbulent reacting flows is introduced based on the Bernstein polynomial. Multi-scalar measurement data of turbulent premixed and non-premixed flames are used to demonstrate that the new functional form provides an excellent reduced-order model for the conditional scalars. This model order reduction technique can be used to improve the accuracy, reduce the computational cost and enhance the spatial localization of the Conditional Source-term Estimation (CSE) model. CSE is a turbulence-chemistry interaction model similar to the Conditional Moment Closure (CMC) model, except that the conditional scalars are estimated from the...
Energy efficiency through joint routing and function placement in different modes of SDN/NFV networks
, Article Computer Networks ; Volume 200 , 2021 ; 13891286 (ISSN) ; Parsaeefard, S ; Maddah Ali, M. A ; Shah-Mansouri, V ; Khalaj, B. H ; Bennis, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Network function virtualization (NFV) and software-defined networking (SDN) are two promising technologies to enable 5G and 6G services and achieve cost reduction, network scalability, and deployment flexibility. However, migration to full SDN/NFV networks in order to serve these services is a time-consuming process and costly for mobile operators. This paper focuses on energy efficiency during the transition of mobile core networks (MCN) to full SDN/NFV networks and explores how energy efficiency can be addressed during such migration. We propose a general system model containing a combination of legacy nodes and links, in addition to newly introduced NFV and SDN nodes. We refer to this...
BIM-based approach to conduct Life Cycle Cost Analysis of resilient buildings at the conceptual stage
, Article Automation in Construction ; Volume 123 , 2021 ; 09265805 (ISSN) ; Jalaei, F ; Golpour, A ; Hosseini Varzande, S. S ; Guest, G ; Sharif University of Technology
Elsevier B.V
2021
Abstract
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...
Weak visibility counting in simple polygons
, Article Journal of Computational and Applied Mathematics ; Volume 288 , November , 2015 , Pages 215-222 ; 03770427 (ISSN) ; Daneshpajouh, S ; Alipour, S ; Ghodsi, M ; Sharif University of Technology
Elsevier
2015
Abstract
For a simple polygon P of size n, we define weak visibility counting problem (WVCP) as finding the number of visible segments of P from a query line segment pq. We present different algorithms to compute WVCP in sub-linear time. In our first algorithm, we spend O(n7) time to preprocess the polygon and build a data structure of size O(n6), so that we can optimally answer WVCP in O(logn) time. Then, we reduce the preprocessing costs to O(n4+ε) time and space at the expense of more query time of O(log5n). We also obtain a trade-off between preprocessing and query time costs. Finally, we propose an approximation method to reduce the preprocessing costs to O(n2) time and space and O(n1/2+ε) query...
An enterprise-grade open-source data reduction architecture for all-flash storage systems
, Article Proceedings of the ACM on Measurement and Analysis of Computing Systems ; Volume 6, Issue 2 , 2022 ; 24761249 (ISSN) ; Raaf, P ; Kishani, M ; Salkhordeh, R ; Asadi, H ; Brinkmann, A ; Sharif University of Technology
Association for Computing Machinery
2022
Abstract
All-flash storage (AFS) systems have become an essential infrastructure component to support enterprise applications, where sub-millisecond latency and very high throughput are required. Nevertheless, the price per capacity ofsolid-state drives (SSDs) is relatively high, which has encouraged system architects to adoptdata reduction techniques, mainlydeduplication andcompression, in enterprise storage solutions. To provide higher reliability and performance, SSDs are typically grouped usingredundant array of independent disk (RAID) configurations. Data reduction on top of RAID arrays, however, adds I/O overheads and also complicates the I/O patterns redirected to the underlying backend SSDs,...
Technical assessment of ground-source, air-source, and hybrid heat pumps for single-family buildings in cold climates
, Article 25 June 2016 through 29 June 2016 ; Volume 122 , 2016 , Pages 270-280 ; 00012505 (ISSN) ; 9781939200464 (ISBN) ; Hakkaki Fard, A. M ; Aidoun, Z ; Ouzzane, M ; Sharif University of Technology
Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc
Abstract
This paper discusses a technical comparison of a directexpansion ground-source heat pump (DX-GSHP) and an airsource heat pump (ASHP). To lower the ground heat exchanger size for cost reduction purposes, the system performance of a hybrid system is also evaluated using a supplementary air evaporator combined with the DX-GSHP. Detailed screening models previously developed for ASHPs and DX-GHSPs are first used to compare the seasonal performance of these two options for a residential building in the cold-climate city of Montreal, Canada. Then, the model is adopted for performance evaluation of the hybrid system. Additionally, different parameters including borehole total length and heat pump...
Optimal distribution network automation considering earth fault events
, Article IEEE Transactions on Smart Grid ; Vol. 6, issue. 2 , 2015 , p. 1010-1018 ; ISSN: 19493053 ; Safdarian, A ; Lehtonen, M ; Fotuhi-Firuzabad, M ; Sharif University of Technology
Abstract
In the past decade, distribution network operators have been broadly engrossed toward automated distribution networks. The operators acknowledge network automation as an efficient investment toward a better service reliability. This paper aims to provide a new long-term cost/benefit analysis for an optimal level of distribution network automation. In the analysis, reduction in customer outage cost is considered as the benefit of implementing automation systems with capital investment, and annual operation and maintenance costs. In the Finnish regulation model, there is a special incentive based on customer outage cost reduction. As the main contribution of this paper, the impact of earth...