Sharif Digital Repository

This paper presents an analytical approach to estimate the speedup in a simulation-emulation cooperation environment. The speedup of this approach as compared with the speedup of a pure simulation is analyzed. Also, an analysis of the speedup is given when different types of application instructions are utilized. The analysis is based on using both Verilog and VHDL. The results show that when only the simulation part of the simulation-emulation co-operation is used, the speedup is higher, than when the pure simulation is used. The total speedup is also depended on the type of application instructions and the communication cycle time between the simulator and the emulator. © 2002 IEEE  

In this paper, we establish the existence and uniqueness of the mild solution for stochastic Volterra equation with a non-self-adjoint operator. The specific Volterra equation that we consider is a generalization of the fractional differential equation. To obtain the mild solution for the case of multiplicative problem, the resolvent property of the linear perturbation of a sectorial operator will be considered. © 2023 World Scientific Publishing Company  

Given two arbitrary pure states |φ〉 and |ψ〉 of qubits or higher level states, we provide arguments in favor of states of the form (1/√2)(|ψ〉|φ〉 + i|φ〉|ψ〉) instead of symmetric or anti-symmetric states, as natural candidates for optimally entangled states constructed from these states. We show that such states, firstly have on the average a high value of concurrence, secondly can be constructed by a universal unitary operator independent of the input states. We also show that these states are the only ones which can be produced with perfect fidelity, by any quantum operation designed for intertwining two pure states with a relative phase. A probabilistic method is proposed for producing any... 

In this paper a scheduling optimization framework is developed to enhance power plants operational decision making process. The proposed framework optimizes plant schedule including operating conditions and maintenance intervals simultaneously and on an hourly basis. In a long term operation plant performance deteriorates due to components aging. This study employs equivalent operating hour (EOH) approach to describe components aging impact on the plant performance deterioration and consequently plant long term profit. Modeling of components aging increases system simulation accuracy in long term operation and the optimum decision variables would be more reliable and realistic. Validity and... 

In the present study a comprehensive thermodynamic model and degradation based optimization framework for energy management of anode supported solid oxide fuel cell (SOFC) stacks are carried out. The optimization framework determines optimum operating conditions to maximize system productivity (energy generation over system lifetime) considering degradation mechanisms. The main degradation mechanisms in anode supported SOFCs are nickel coarsening and oxidation. In this study, the optimum operating conditions regarding these degradation mechanisms to achieve maximum productivity at different target lifetimes are derived. The results show that target lifetime has a significant impact on system... 

In this work a microgrid is established within the geographical perspective of interest. The characteristics of the grid and its urban are employed to determine the candidate points for establishment of EV charging stations. The investment costs and operation costs are calculated for each station realizing the required constraints. This process resulted in optimum selection of EV stations. The optimization is achieved based on two different types of preliminary assumptions. In the first one, it is assumed to have only one station, while in the second one possibility of having multi-stations is considered. Using the total investment and operation costs as the objective function of... 

Performance degradation remains as one of the primary limitations for practical applications of proton exchange membrane (PEM) fuel cells. The performance of a PEM fuel cell stack is affected by many internal and external factors, such as fuel cell design and assembly, degradation of materials, operational conditions, and impurities or contaminants. Performance degradation is unavoidable, but the degradation rate can be minimized through a comprehensive understanding of degradation and failure mechanisms. In present work, a single PEM fuel cell for stationary applications is investigated. Membrane and catalyst layers (anode and cathode electrodes) are considered as critical components that... 

The paper presents a novel vector control structure for the Brushless Doubly-Fed Machine (BDFM) which is derived based on the machine synchronous operation. In fact, the synchronous operation of the BDFM provides an efficient approach for determining the required reference angle in the machine vector control structure. The utilization of such reference angle makes the vector control structure presented in this paper different from and, in fact, more effective than the existing rotor flux and stator flux orientation schemes proposed for the machine. The results of implementing the vector control scheme in simulations confirm the effectiveness of the proposed approach for the BDFM control  

Chatter is a limiting factor in machining systems with adverse effects for workpiece surface, tool and machine life and material removal rate. Proper modelling of this phenomenon requires that the dynamic characteristics of the machining system is known. It is common to obtain the dynamic of the system by modal tests in stationary condition. However, the vibration characteristics of a machine change between its operating and resting mode. The goal of this work is to study vibrations in boring using the vibrational characteristic in operational conditions using the operating deflection shape method. In this paper, vibration characteristics of the in the boring bar is obtained by both modal... 

In this note, we show that under certain assumptions the scalar Riccati differential equation x′=a(t)x+b(t)x 2+c(t) with periodic coefficients admits at least one periodic solution. Also, we give two illustrative examples in order to indicate the validity of the assumptions  

Aerial firefighting plays an integral role in containing wildfires, which have been growing rapidly in frequency and intensity over the past decades. However, the current aerial-resource management models were developed decades ago, based on the technology available then. This research aims to investigate how and what modern technologies can be integrated into aerial firefighting operation to help it keep up with the worsening situation. DSM has been used as an engineering tool to decompose the complex problem space into separate manageable segments. Using a task-based DSM, the interdependencies which give rise to unnecessary complexities are visualized, and the potential to integrate new... 

Outpatient appointment scheduling problems have recently gained increasing attention. This paper provides a comprehensive review of recent analytical and numerical optimization studies that present decision-support tools for designing and planning outpatient appointment systems (OASs). A structure for organizing the recent literature according to various criteria is provided, including a framework that classifies decisions at the strategic, tactical, and operational levels. The OAS literature is evaluated from four perspectives: problem settings, environmental factors, modeling approaches, and solution methods. In addition, research gaps and areas of opportunity for future research are... 

People use trust to cope with uncertainty which is a result of the free will of others. Previous approaches for inferring trust have focused on homogeneous relationships and attempted to infer missing information based on existing information in a single relationship. In this paper we propose using methods of social network analysis to infer trust in a heterogeneous social network. We have extended the problem of relation extraction and allowed using any type of binary operator on matrixes, whereas previous work have focused on linear combination of base matrixes (the only allowed operator was summation of two matrixes). We present two genetic algorithms which use ordinary numerical and... 

Constraint automata have been proposed as the operational semantics of Reo, a glue-code language for the exogenous composition and orchestration of components in a software system. In this paper we recast the theory of constraint automata into that of Büchi automata on infinite strings of records. We use records to express simultaneity constraints of I/O operations and show that every constraint automaton can be expressed as a Büchi automaton on an appropriate alphabet of records. Further, we give examples of component compositions that are expressible as Büchi automata but not as constraint automata. Finally, we show that the join composition operator for constraint automata and its... 

We introduce the notion of private set operations (PSO) as a symmetric-key primitive in the cloud scenario, where a client securely outsources his dataset to a cloud service provider and later privately issues queries in the form of common set operations. We define a syntax and security notion for PSO and propose a general construction that satisfies it. There are two main ingredients to our PSO scheme: an adjustable join (Adjoin) scheme (MIT-CSAIL-TR-2012-006 (2012) Cryptographic treatment of CryptDB's adjustable join. http://people.csail.mit.edu/nickolai/papers/popa-join-tr.pdf) and a tuple set (TSet) scheme (Cash, D., Jarecki, S., Jutla, C. S., Krawczyk, H., Rosu, M.-C., and Steiner, M.... 

In the context of sustainable clean hydrogen production pathways, photovoltaic-electrolyzer systems are one of the most promising alternatives for acquiring hydrogen from renewable energy sources. In fact, determining the optimal set of design and operating variables are always a key issue while coupling directly renewable electricity sources to PEM electrolyzers. Few previous studies have attempted to find the optimal size and operational condition of directly coupled photovoltaic-electrolyzer (PV/El) systems in order to maximize the hydrogen production or to minimize energy transfer loss between photovoltaic devices and the electrolyzer. Nevertheless an easy and efficient approach still...