Sharif Digital Repository

Traditional regulatory models of natural monopoly network utilities are designed to incentivise cost-efficiency, subject to the firm achieving a certain level of reliability. With the rise of decarbonisation as a key policy goal, facilitating innovation in electricity networks has become of vital importance. Innovation and cost-efficiency may overlap and exhibit the same risk profile. However, we show that when there is a difference in their risk profile, incentivising these two tasks using the same incentive scheme is ineffective. This means incentive regulations need to be enhanced with additional modules that take into account the level of risk to which companies are exposed to for their... 

The concerns of regulatory authority for the cost efficiency and service quality of distribution utilities has led them to implement monetary schemes, such as penalty/reward mechanism (PRM). PRM provides explicit financial incentives for distribution system operators (DSO) to maintain or improve their efficiency and quality of service. Although the effectiveness of the PRM is proven, analytical tools that can handle the complex decision-making process faced by decision makers to respond to PRM are scarce. This paper presents an approach for distribution system maintenance management in the presence of the PRM. The proposed approach tailors the maintenance plans by taking into account the... 

Fast, accurate, and detailed Soft Error Rate (SER) estimation of digital circuits is essential for cost-efficient reliable design. A major step to accurately estimate a circuit SER is the computation of failure probability, which requires the computation of three derating factors, namely logical, electrical, and timing derating. The unified treatment of these derating factors is crucial to obtain accurate failure probability. Existing SER estimation techniques are either unscalable to large circuits or inaccurate due to lack of unified treatment of all derating factors. In this paper, we present fast and efficient algorithms to estimate SERs of circuit components in the presence of single... 

The concerns of regulatory authority for the cost efficiency and service quality of distribution utilities has led them to implement monetary schemes, such as penalty/reward mechanism (PRM). PRM provides explicit financial incentives for distribution system operators (DSO) to maintain or improve their efficiency and quality of service. Although the effectiveness of the PRM is proven, analytical tools that can handle the complex decision-making process faced by decision makers to respond to PRM are scarce. This paper presents an approach for distribution system maintenance management in the presence of the PRM. The proposed approach tailors the maintenance plans by taking into account the... 

This paper shows a new possible way with particle swarm optimisation (PSO) to achieve an exergoeconomic optimisation of combinedcycle power plants. The optimisation has been done using a classic exergoeconomic and genetic algorithm, and the effects of using three methods are investigated and compared. The design data of an existing plant is used for the present analysis. Two different objective functions are proposed: One minimises the total cost of production per unit of output, and maximises the total exergetic efficiency. The analysis shows that the total cost of production per unit of output is 2%, 3%and 5% lower and exergy efficiency is 4%, 8% and 6% higher with respect to the base case... 

Data transmission in Network-on-Chips (NoCs) is a serious problem due to crosstalk faults happening in adjacent communication links. This paper proposes an efficient flow-control method to enhance the reliability of packet transmission in Network-on-Chips. The method investigates the opposite direction transitions appearing between flits of a packet to reorder the flits in the packet. Flits are reordered in a fixed-size window to reduce: 1) the probability of crosstalk occurrence, and 2) the total power consumed for packet delivery. The proposed flow-control method is evaluated by a VHDL-based simulator under different window sizes and various channel widths. Simulation results enable NoC... 

This paper presents a cost-efficient technique to jointly use circuit- and architecture-level techniques to protect an embedded processor's register file against soft errors. The basic idea behind the proposed technique is robust register caching (RRC), which creates a cache of the most vulnerable registers within the register file in a small and highly robust cache memory built from circuit-level single-event-upset-protected memory cells. To guarantee that the most vulnerable registers are always stored in the robust register cache, the average number of read operations during a register's lifetime is used as a metric to guide the cache replacement policy. A register is vulnerable to soft... 

Phase Change Memory (PCM) is emerging as a high-dense and power-efficient choice for future main memory systems. While PCM cell size is marching towards minimum achievable feature size, recent prototypes effectively improve device scalability by storing multiple bits per each cell. Unfortunately, Multi-Level Cell (MLC) PCM devices offer higher access time and energy when compared to Single-Level Cell (SLC) counterparts making it difficult to incorporate MLC in main memory. To address this challenge, we proposes Zero-value-based Morphable PCM, ZM-PCM for short, a novel MLC-PCM main memory architecture which tries incorporating benefits of both MLC and SLC devices within the same structure.... 

Rapid market changes, explosion of product varieties and short life cycleshave increased competition in today's global markets. It is obvious that intoday's competitive markets, collaboration between the vendor and the buyer isnecessary to reduce the joint inventory cost and the response time of thevendor-buyer system. Joint Economic Lot sizing Problem has been extended in manydifferent directions. Shortage is not allowed in the most of the previousresearches. A few of them considered shortage backordering as a result ofimperfect quality. The purpose of this paper is to recast the Joint economic lotsizing model to be more relevant to current situations, where lost sales and/orbackorders are... 

Waterflooding has been regarded as an efficient method for pressure maintenance of oil reservoirs. x Improved techniques such as Smart Water flooding as a new EOR/IOR process has gained more momentum based on the recent research activities in this field and the reduction of oil price. Despite many efforts on achieving the governing mechanisms of Smart Water flooding in many individual fields, most of data are sparse and more possible mechanisms which explains all the interactions yet to be introduced. This experimental study used a systematic laboratory framework which is based on seawater treatments at fixed ionic strength to eliminate the ionic strength effects, NaCl considered as the... 

A study of the wheel and rail wear phenomenon can provide a chance for the optimal use of wheel profile, which results in cost efficiency, dynamic stability, travel comfort, and safety to prevent the derailment, especially in curves. In this paper, the experimental data are recorded based on the field measurements for worn wheels of a passenger wagon in the "Southern line" of Iran's railway system and are combined with the dynamic simulations to study the effects of severe wheel flange wear on the dynamics of wagon. The results show that the amount of wheel wear (especially the wheel flange) directly impacts the dynamic behavior of the wagon in curves. In addition, based on the history of... 

A study of the wheel and rail wear phenomenon can provide a chance for the optimal use of wheel profile, which results in cost efficiency, dynamic stability, travel comfort, and safety to prevent the derailment, especially in curves. In this paper, the experimental data are recorded based on the field measurements for worn wheels of a passenger wagon in the "Southern line" of Iran's railway system and are combined with the dynamic simulations to study the effects of severe wheel flange wear on the dynamics of wagon. The results show that the amount of wheel wear (especially the wheel flange) directly impacts the dynamic behavior of the wagon in curves. In addition, based on the history of... 

Perovskite solar cells are well known for being low cost, solution-based, and efficient solar cells; however, the high price of the conventional hole-collector electrode (Spiro-OMeTAD/Gold) and the high price and complexity of depositing gold on large scales are major barriers against commercializing them. Herein, an effective carbon composite electrode is introduced for a low-cost perovskite solar cell with CuIn0.75Ga0.25S2 hole transport material to solve this problem. The carbon electrode is deposited by the doctor blade method using a paste composed of flakes of graphite, carbon black, and a kind of hydrophobic polymer (polystyrene or poly-methyl methacrylate). It is investigated how the... 

Perovskite solar cells (PSCs) have excellent photovoltaic properties. There are, however, challenges of materials cost and device stability to be solved before commercializing them. Utilizing low-cost inorganic hole transport materials (HTM) as a replacement for spiro-OMeTAD, and replacing the Au electrode with printable carbon could be important steps in this regard. For this purpose, CuInxGa1-xS2 (x = 1, 0.75, 0.5, 0.25, 0) nanoparticle layers are deposited as inorganic HTMs with carbon composite electrode as the back electrode. Photovoltaic properties of PSCs with CuInxGa1-xS2/Carbon hole collecting electrodes are studied by changing the In ratio in the HTM layer. Results from impedance... 

In New applications of Mobile Ad hoc Networks (MANETs), nodes may decide not to cooperate in routing protocols in order to save their limited resources while still using the network to relay their own traffic. Exhibiting such a selfish behavior by even a few nodes may degrade network performance and other cooperating nodes may find themselves unfairly loaded. To cope with such a situation, we propose a Stable path, Low overhead, Truthful, and Cost efficient (SLTC) routing protocol which stimulates nodes to cooperate and act truthfully by utilizing the game theoretic notion of mechanism design. To the best of our knowledge, SLTC is the first protocol attaining the message complexity of O(nd),... 

A novel microspherical adsorbent for the removal of uranium from aqueous solutions was developed by immobilizing of natural bentonite in the polymeric matrix of calcium alginate. Different uptake properties of the prepared microspheres were examined using batch, stirred and column methods. The adsorbent showed high affinity toward uranium ions, especially at pHs above 3. Major uptake mechanisms included ion exchange, chelating of the (UO2)2+ ions to the -OH groups of alginate, and surface complexation with bentonite. Surprisingly, the capacity of microspheres was higher than both its constituents, revealing that a synergetic effect occurs. Adsorption kinetics was controlled by slow chemical... 

The current study aims to simultaneously and comprehensively investigate the performance of four types of recuperative heat exchangers applied in 200 kW microturbines by using numerical method. Different fin configurations including rectangular, triangular, louver and offset strip fins are employed in the recuperators to enhance the heat transfer rate. Additionally, the calculations are separately undertaken for both counter and cross-flow arrangements. To achieve the best performance, a three-objective optimization problem is solved using Non-dominated Sorting Genetic Algorithm (NSGA-II). Recuperator effectiveness and exergy efficiency and total cost are considered as the objective... 

Network-on-Chips are now the popular communication medium to support inter-IP communications in complex on-chip systems with tens to hundreds IP cores. Higher scalability (compared to the traditional shared bus and point-to-point interconnects), throughput, and reliability are among the most important advantages of NoCs. Moreover, NoCs can well match current CAD methodologies mainly relying on modular and reusable structures with regularity of structural pattern. However, since NoCs are resource-limited, determining how to distribute application load over limited on-chip resources (e.g. switches, buffers, virtual channels, and wires) in order to improve the metrics of interest and satisfy... 

Efficient environmental management calls for the consideration of multiple pollutants, for which two main types of transferable discharge permit (TDP) program have been described: separate permits that manage each pollutant individually in separate markets, with each permit based on the quantity of the pollutant or its environmental effects, and weighted-sum permits that aggregate several pollutants as a single commodity to be traded in a single market. In this paper, we perform a mathematical analysis of TDP programs for multiple pollutants that jointly affect the environment (i.e., interactive pollutants) and demonstrate the practicality of this approach for cost-efficient maintenance of...