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Metal-insulator transition in a ternary model with long range correlated disorder
, Article Journal of Statistical Mechanics: Theory and Experiment ; Issue 9 , 2007 ; 17425468 (ISSN) ; Cheraghchi, H ; Carpena, P ; Rahimi Tabar, M. R ; Sharif University of Technology
2007
Abstract
We study the metal-insulator transition of the one-dimensional diagonal Anderson ternary model with long range correlated disorder. The starting point of the model corresponds to a ternary alloy (i.e. with three possible on-site energies), and shows a metal-insulator transition when the random distribution of site energies is assumed to have a power spectrum S(k) ∝ 1/k (2α-1). In this paper, we define a purity parameter for the ternary alloy which adjusts the occupancy probability of site potentials, and for any given α we calculate the critical purity parameter for which extended states are obtained. In this way, we show that the ternary alloy requires weaker correlations than the binary...
Statistical properties of a localization-delocalization transition induced by correlated disorder
, Article Journal of Statistical Mechanics: Theory and Experiment ; Issue 11 , 2006 ; 17425468 (ISSN) ; Fazeli, S. M ; Sharif University of Technology
2006
Abstract
The exact probability distributions of the resistance, the conductance and the transmission are calculated for the one-dimensional Anderson model with long-range correlated off-diagonal disorder at E = 0. It is proved that despite the Anderson transition in 3D, the functional forms of the resistance and its related variables distribution functions do not vary when there exists a metal-insulator transition induced by a correlation among disorders. Furthermore, we derive analytically all statistical moments of the resistance, the transmission and the Lyapunov exponent. The rate of growth of the resistance with the length decreases as the Hurst exponent H tends to its critical value (Hcr = 1/2)...
A general model for I/O system theory, Proceedings of AIMC31 [electronic resource]
, Article Iranian Journal of Fuzzy Systems ; 2006, Volume 3, Issue 2, Page 1-19 ; Hashem, Amir ; Sharif University of TechnologyGenerating Bell states in invariant stratification spin networks
, Article Journal of Statistical Mechanics: Theory and Experiment ; Volume 2010, Issue 12 , 2010 ; 17425468 (ISSN) ; Jafarizadeh, M. A ; Rouhani, S ; Sharif University of Technology
Abstract
In this paper, we study the generation of Bell states between distant vertices in a permanently coupled quantum spin network, interacting via invariant stratification graphs. To begin with we establish a class of upper bounds over the achievable entanglement between the reference site and various vertices. We observe that the maximum of these upper bounds is one e-bit. We conclude that the reference site can generate a Bell state with a vertex if the corresponding upper bound of the vertex is one e-bit. Thus for generation of a Bell state this upper bound must be saturated. Taking this into account, we obtain the characteristic constraint of the proper graphs. We introduce a special class of...
The provision of optimal entanglement on underlying networks of group association schemes
, Article Journal of Statistical Mechanics: Theory and Experiment ; Volume 2010, Issue 3 , 2010 ; 17425468 (ISSN) ; Jafarizadeh, M. A ; Rouhani, S ; Sharif University of Technology
Abstract
We investigate the creation of optimal entanglement in axially symmetric networks. The proposed network is one in which the connections are organized using a group table - in other words, using group association schemes. We show that optimal entanglement can be provided on such networks by adjusting couplings and the initial state. We find that the optimal initial state is a simple locally excited state. Moreover we obtain an analytic formula for the entanglement achievable between vertex pairs located in the same or conjugate strata and calculate their relevant optimal couplings. For those pairs located in non-conjugate strata, two upper bounds are presented. These results are also checked...
Scaling properties of one-dimensional off-diagonal disorder
, Article Journal of Statistical Mechanics: Theory and Experiment ; Issue 11 , 2006 ; 17425468 (ISSN) ; Sharif University of Technology
2006
Abstract
Validity of the single-parameter scaling (SPS) in the one-dimensional Anderson model with purely off-diagonal disorder is studied. It is shown that the localized region with standard symmetry is divided into two regimes: SPS and non-SPS. Moreover, the scaling relations for the Lyapunov exponent are proposed for these two regimes. In the non-SPS regime, in addition to the localization length, there exists a new length scale which is related to the integral density of states. A physical interpretation of the new length is as the crossover length which separates regions with chiral symmetry from those with standard symmetry. © 2006 IOP Publishing Ltd and SISSA
Fuzzy sets from a meta-system-theoretic point of view
, Article Iranian Journal of Fuzzy Systems ; Volume 3, Issue 2 , 2006 , Pages 1-19 ; 17350654 (ISSN) ; Hashemi, A ; Sharif University of Technology
2006
Abstract
In this paper we present, for the first time, complete proofs of the facts that have already been announced in [A. Daneshgar, A. Hashemi, A general model for I/O system theory, Proc. AIMC31, 2000, 292-299]. Our approach here is to focus on the aspects related to fuzzy set theory and we leave other connections to mathematical disciplines such as quantum groups, categorical logic, homological algebra and measure theory to appear elsewhere. The main contribution is to introduce a general framework based on enriched category theory that covers the theory of translation invariant systems as a special case, as well as the construction of the Haar fraction on a locally compact group
Short-term market power assessment in a long-term dynamic modeling of capacity investment
, Article IEEE Transactions on Power Systems ; Volume 28, Issue 2 , October , 2013 , Pages 626-638 ; 08858950 (ISSN) ; Hosseini, S. H ; Sharif University of Technology
2013
Abstract
This paper proposes a dynamic time simulation model for long-term generation capacity investment decisions in the presence of either perfect or imperfect electricity market. The model is based on system dynamics concept in which the dynamics of capacity construction is traced using the forecast of electricity price cleared in the short-term electricity market. Both the perfect and oligopolistic competitions are considered and a market power index is defined to evaluate the competition level of the electricity market. The short-term and long-term dynamic analysis are used to represent the generation firms' behavior in bidding strategy and capacity investment, respectively. Both possibilities...
Ball striking algorithm for a 3 DOF ping-pong playing robot based on particle swarm optimization
, Article 2012 16th International Conference on System Theory, Control and Computing, ICSTCC 2012 - Joint Conference Proceedings ; 2012 ; 9786068348483 (ISBN) ; Nooranidoost, M ; Enghiad, B ; Hajimirzakhani, A ; Sharif University of Technology
2012
Abstract
This paper illustrates how a 3 degrees of freedom, Cartesian robot can be given the task of playing ping-pong against a human player. We present an algorithm based on particle swarm optimization for the robot to calculate when and how to hit an approaching ball. Simulation results are shown to depict the effectiveness of our approach. Although emphasis is placed on sending the ball to a desired point on the ping pong table, it is shown that our method may be adjusted to meet the requirements of a variety of ball hitting strategies
Performance evaluation of water resources systems using system dynamics approach: Application to the Aras River Basin, Iran
, Article World Environmental and Water Resources Congress 2012: Crossing Boundaries, Proceedings of the 2012 Congress ; 2012 , Pages 2367-2377 ; 9780784412312 (ISBN) ; Abrishamchi, A ; Sharif University of Technology
ASCE
2012
Abstract
System Dynamics approach is a powerful tool in water resources systems simulation for evaluating proposed plans and policies in development projects. In Aras River basin, existing water resources do not suffice increasing demand in the near future, thus construction of new reservoirs is under study. In this study, system dynamics approach is used to simulate the water resources system of Darehrood sub basin located in eastern part of Aras River basin. Performance indices are used to evaluate the alternative plans and policies.. Reliability, resiliency and vulnerability, the three performance indices used in study, are estimated using maximum value and mean value estimators mentioned in the...
Dynamics of knowledge accumulation in technology follower countries: A system dynamics approach
, Article Journal of Systems Science and Systems Engineering ; Volume 18, Issue 3 , 2009 , Pages 312-340 ; 10043756 (ISSN) ; Ghofrani, M. B ; Saboohi, Y ; Sharif University of Technology
2009
Abstract
In this paper the process of knowledge accumulation for a particular technology is studied. Two countries, say the technology follower and the technology frontier, are considered. The frontier's knowledge growth is determined by its R&D efforts on the technology. The level of knowledge stock for the follower country is augmented by its R&D activities for the technology and absorbing some of the external knowledge through spillover from the frontier. The extent to which the follower is able to exploit the external knowledge depends on technological gap, absorptive capacity, absorption time and degree of spillover. New concepts such as natural and enhanced degree of spillover, background and...
Correlation-Picture approach to open-quantum-system dynamics
, Article Physical Review X ; Volume 10, Issue 4 , 2020 ; Rezakhani, A. T ; Babu, A. P ; Mølmer, K ; Möttönen, M ; Ala-Nissila, T ; Sharif University of Technology
American Physical Society
2020
Abstract
We introduce a dynamical picture, referred to as correlation picture, which connects a correlated bipartite state to its uncorrelated counterpart. This picture allows us to derive an exact dynamical equation for a general open-system dynamics with system-environment correlations included. This exact dynamics is in the form of a Lindblad-like equation even in the presence of initial system-environment correlations. For explicit calculations, we also develop a weak-correlation expansion that allows us to introduce systematic perturbative approximations. This expansion provides approximate master equations that can feature advantages over existing weak-coupling techniques. As a special case, we...
Resisting dynamic structures in shifting toward "systems thinking"
, Article 51st Annual Meeting of the International Society for the Systems Sciences, ISSS 2007, Tokyo, 5 August 2007 through 10 August 2007 ; 2007 , Pages 593-611 ; 9781605600437 (ISBN) ; Fakhar Izadi, E ; Moteabbed, S ; Sharif University of Technology
2007
Abstract
There is a unanimous agreement that "systems thinking" helps both individuals and organizations make more intelligent and more effective decisions. On the other hand, the unsatisfactory rate of systems thinking evolution among managers, collegians, students and other stratums raises this question that, why such a useful, discriminating and tasteful concept in theory, does not spread with the desirable pace in practice. Where exactly does the problem originate from? The tragedy is more sensible when noting the fact that even those who know the concept methodically do not apply it in action and in their decisions. Unfortunately, despite relatively numerous literatures on changing beliefs,...
The impact of customer knowledge on the organizational performance: a system dynamics approach
, Article Kybernetes ; 2021 ; 0368492X (ISSN) ; Owlia, M. S ; Isaai, M. T ; Sharif University of Technology
Emerald Group Holdings Ltd
2021
Abstract
Purpose: The purpose of this research was to model the impact of customer knowledge on the performance of organization with a focus on information technology industry. Furthermore, it is intended to analyze the effect of customer knowledge investment on the performance measures, by reviewing investment policies. Design/methodology/approach: The relationship between customer knowledge and performance measures was specified using literature review and grounded theory method. The system dynamics approach was then applied to analyze the impact of the customer knowledge on the performance measures. Findings: This study provided a dynamic model on the causal relationship between customer knowledge...
A system dynamics approach to analyze water resources systems
, Article 31st IAHR Congress 2005: Water Engineering for the Future, Choices and Challenges, 11 September 2005 through 16 September 2005 ; 2005 , Pages 4991-5000 ; 8987898245 (ISBN); 9788987898247 (ISBN) ; Baradarannia, M.R ; Sarang, A ; Hjorth, P ; Byong-Ho J ; Sang I.L ; Won S.I ; Gye-Woon C ; Sharif University of Technology
Korea Water Resources Association
2005
Abstract
Several mathematical modeling approaches are used to model water resources systems such as deterministic and non-deterministic, lumped and distributed, steady and dynamic, simulation and optimization approaches. All these modeling paradigms - categorized as open systems - assume that the input conditions to the system will not change during their operation. What is happening in the real world is somewhat different. Due to their dynamic behaviors, real world events exert feedbacks from their outputs to their inputs which may cause the input conditions vary with time. This is the main focus of the system dynamics theory which has been introduced in this paper to be applied in water resources...
Analogy Indices in the Engineering of Large Socio-Economic Systems (With Emphasis on Aerospace Education Systems)
, M.Sc. Thesis Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor)
Abstract
Throughout the history of science, mankind has always invented tools and methods to help him deal with complex problems, means that constitute the science. Systems theory and all the tools and methods introduced by it to analyze and judge simple to complex systems, although relatively recent, has left an enormous impact on current life style by being one those very important sciences that make dealing with complex systems easier. On the other hand, the importance of educational systems and their impact over the success of societies and large systems is close to obvious. In today’s world, having an effective educational system which can deliver required information to people and prepare them...
Dynamic interactions of TGC and electricity markets to promote wind capacity investment
, Article IEEE Systems Journal ; Volume 6, Issue 1 , 2012 , Pages 46-57 ; 19328184 (ISSN) ; Hosseini, S. H ; Sharif University of Technology
Abstract
This paper proposes a time simulation model for long-term wind capacity investment decisions in the presence of electricity market and tradable green certificate (TGC) market. Investment decisions and wind capacity development are fundamentally based on incentives gained from both these markets. In TGC market, the tradable certificates are issued to renewable generation companies for each megawatt-hour of electricity generation. Distribution companies are obligated to support fraction of their electricity consumptions from renewable sources. The dynamics of prices in both markets are simulated in a system dynamics model to trace the dynamics of wind capacity investment. Such a decision model...
Dynamic assessment of capacity investment in electricity market considering complementary capacity mechanisms
, Article Energy ; Volume 36, Issue 1 , January , 2011 , Pages 277-293 ; 03605442 (ISSN) ; Hosseini, S. H ; Sharif University of Technology
2011
Abstract
This paper proposes a decentralized market-based model for long-term capacity investment decisions in a liberalized electricity market. Investment decisions are fundamentally based on total revenues gained by investors. In most electricity markets, the complementary mechanisms are designed to ensure a desired level of reliability while covering investment costs of the suppliers. In such an environment, investment decisions are highly sensitive to expectation of price signals in both of energy market and capacity mechanisms. In this work, the system dynamics concepts are used to model the structural characteristics of electricity market such as, long-term firms' behavior and relationships...
Robust multiple model adaptive control using fuzzy fusion
, Article 2010 42nd Southeastern Symposium on System Theory, SSST 2010, Tyler, TX, 7 March 2010 through 9 March 2010 ; March , 2010 , Pages 19-24 ; 9781424456901 (ISBN) ; Dumont, G. A ; Feyz Mahdavian, H. R ; Sharif University of Technology
2010
Abstract
A robust multiple model adaptive control strategy using fuzzy fusion (RMMAC-FF) is presented in this paper. The main idea in multi-model controllers is to identify the best model of the system at any instant of time and apply the appropriate control input to it. RMMAC-FF, integrates a fuzzy robust controller, with the fuzzy multiple model adaptive estimation and a fuzzy switching to come up with a new strong methodology to control complex systems. Simulation results of the RMMAC-FF on a two-cart system, used as a benchmark problem, verify the theory and confirm the effectiveness of the proposed controller
Airlines maintenance cost analysis using system dynamics modeling
, Article 30th Congress of the International Council of the Aeronautical Sciences, ICAS 2016, 25 September 2016 through 30 September 2016 ; 2016 ; 9783932182853 (ISBN) ; Farkhondeh, F ; Khalili, N ; Abedian, A ; Sharif University of Technology
International Council of the Aeronautical Sciences
2016
Abstract
Maintenance costs in airlines change as time passes. As airplane ages, it needs more often and more expensive checks. Due to these growing expenses, airlines are getting more interested in cost analysis. Under financial pressure, they avoid buying new airplanes and try to maintain the old ones, but sometimes try to cut the maintenance costs by ignoring or delaying some checks. In other words, they are more disposed to spend small amount of money frequently through time, than to spend a great deal on a new airplane with low maintenance costs. Therefore, in such situations, the following questions raise that what solution is more efficient as we look dynamically to the system? For answering...