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    Optimal reserve capacity allocation with consideration of customer reliability requirements

    , Article Energy ; Volume 35, Issue 9 , 2010 , Pages 3883-3890 ; 03605442 (ISSN) Najafi, M ; Ehsan, M ; Fotuhi Firuzabad, M ; Akhavein, A ; Afshar, K ; Sharif University of Technology
    An algorithm for determining optimal reserve capacity in a power market is presented in this paper. Optimization process in the proposed algorithm is based on the cost-benefit trade off. Market clearance is executed with consideration of uncertainties of power system components in an aggregated environment. It is assumed that both generating units and interruptible loads participate in the reserve market. In addition, customers' reliability requirements are considered as constraints for decision making process of ISO. The rendered method considers random outages of generating units and transmission lines and determined outage of interruptible loads and employs Monte Carlo Simulation (MCS)... 

    Development of a dynamic long-term water allocation model for agriculture and industry water demands

    , Article Water Resources Management ; Volume 24, Issue 9 , 2010 , Pages 1717-1746 ; 09204741 (ISSN) Karimi, A ; Ardakanian, R ; Sharif University of Technology
    Demands growth and water resources limitation, enforce water sector policy makers to integrate water supply-demand interactions in a coherent framework for efficient water allocation. Water supply-demand interaction, changes long-term trend of water demands, which in turn has a substantial influence on water allocation. Researches on water allocation modeling lack adequate projection of relationship between water supply and demand. Socio-economic factors representing water allocation stakeholders' benefits, account for the main share of water supply-demand interaction. Identification, representation and consideration of these factors in a water allocation model, is the main limitation of... 

    Network-level pavement roughness prediction model for rehabilitation recommendations

    , Article Transportation Research Record ; Issue 2155 , 2010 , Pages 124-133 ; 03611981 (ISSN) Kargah Ostadi, N ; Stoffels, S. M ; Tabatabaee, N ; Sharif University of Technology
    Pavement performance models are key components of any pavement management system (PMS). These models are used in a network-level PMS to predict future performance of a pavement section and identify the maintenance and rehabilitation needs. They are also used to estimate the network conditions after the application of various maintenance and rehabilitation alternatives and to determine the relative cost effectiveness of each maintenance and rehabilitation alternative. Change in pavement surface roughness over time is one of the most important performance indicators in this regard. A model for changes in the international roughness index (IRI) over time was developed through artificial neural... 

    A reservoir conductivity evaluation using percolation theory

    , Article Petroleum Science and Technology ; Volume 29, Issue 10 , 2011 , Pages 1041-1053 ; 10916466 (ISSN) Sadeghnejad, S ; Masihi, M ; King, P. R ; Shojaei, A ; Pishvaie, M ; Sharif University of Technology
    Oil reservoirs are very complex with geological heterogeneities that appear on all scales. Proper modeling of the spatial distribution of these heterogeneities is crucial, affecting all aspects of flow and, consequently, the reservoir performance. Reservoir connectivity and conductivity evaluation is of great importance for decision-making on various possible development scenarios including infill drilling projects. This can be addressed by using the percolation theory approach. This statistical approach considers a hypothesis that the reservoir can be split into either permeable (good sands) or impermeable flow units (poor sands) and assumes that the continuity of permeability contrasts... 

    Multi-objective node placement considering non-uniform event pattern

    , Article Wireless Personal Communications ; Volume 97, Issue 4 , 2017 , Pages 6189-6220 ; 09296212 (ISSN) Mohtashami, H ; Movaghar, A ; Teshnehlab, M ; Sharif University of Technology
    Ease of use, high flexibility and variety of applications have made wireless sensor networks very popular. Node placement in a sensor network is very critical since it affects important network attributes such as coverage, lifetime, and reliability. Therefore, controlled node placement is necessary for achieving specific network features with minimum number of nodes. Since node placement is an NP-hard problem, many placement algorithms have been proposed based on heuristic and meta-heuristic methods. Most of those algorithms assume a uniform event pattern (UEP) throughout the area under investigation. However, in practice some networks deal with non-uniform event pattern (NEP). Optimization... 

    Spring hydrograph simulation of karstic aquifers: impacts of variable recharge area, intermediate storage and memory effects

    , Article Journal of Hydrology ; Volume 552 , 2017 , Pages 225-240 ; 00221694 (ISSN) Hosseini, S. M ; Ataie Ashtiani, B ; Simmons, C. T ; Sharif University of Technology
    A simple conceptual rainfall–runoff model is proposed for the estimation of groundwater balance components in complex karst aquifers. In the proposed model the effects of memory length of different karst flow systems of base-flow, intermediate-flow, and quick-flow and also time variation of recharge area (RA) during a hydrological year were investigated. The model consists of three sub-models: soil moisture balance (SMB), epikarst balance (EPB), and groundwater balance (GWB) to simulate the daily spring discharge. The SMB and EPB sub-models utilize the mass conservation equation to compute the variation of moisture storages in the soil cover and epikarst, respectively. The GWB sub-model... 

    Integration of fault tree analysis, reliability block diagram and hazard decision tree for industrial robot reliability evaluation

    , Article Industrial Robot ; Volume 44, Issue 6 , 2017 , Pages 754-764 ; 0143991X (ISSN) Fazlollahtabar, H ; Akhavan Niak, S. T ; Sharif University of Technology
    Emerald Group Publishing Ltd  2017
    Purpose - This paper aims to conduct a comprehensive fault tree analysis (FTA) on the critical components of industrial robots. This analysis is integrated with the reliability block diagram (RBD) approach to investigate the robot system reliability. Design/methodology/approach - For practical implementation, a particular autonomous guided vehicle (AGV) system was first modeled. Then, FTA was adopted to model the causes of failures, enabling the probability of success to be determined. In addition, RBD was used to simplify the complex system of the AGV for reliability evaluation purpose. Findings - Hazard decision tree (HDT) was configured to compute the hazards of each component and the... 

    Application of a maintenance management model for iranian railways based on the markov chain and probabilistic dynamic programming

    , Article Scientia Iranica ; Volume 16, Issue 1 A , 2009 , Pages 87-97 ; 10263098 (ISSN) Shafahi, Y ; Hakhamaneshi, R ; Sharif University of Technology
    Railway managers have a strong economic incentive to minimize track maintenance costs, while maintaining safety standards and providing adequate service levels to train operators. The objective of this study is to apply a procedure for making optimal maintenance decisions in Iranian Railways. This study consists of two parts. First, a cumulative damage model, based on a Markov process, is applied to model the deterioration of the track. For this reason, tracks are categorized into six classes, so that those tracks with similar traffic loads and geographical location are collected into one class. The track survey data from 215 blocks (4,228 km) of the ten divisions of the Iranian Railway... 

    A two-phase linear programming methodology for fuzzy multi-objective mixed-model assembly line problem

    , Article International Journal of Advanced Manufacturing Technology ; Volume 44, Issue 9-10 , 2009 , Pages 1010-1023 ; 02683768 (ISSN) Mahdavi, I ; Javadi, B ; Sahebjamnia, N ; Mahdavi Amiri, N ; Sharif University of Technology
    We develop a fuzzy multi-objective linear programming (FMOLP) model for solving multi-objective mixed-model assembly line problem. In practice, vagueness and imprecision of the goals in this problem make the fuzzy decision-making complicated. The proposed model considers minimizing total utility work, total production rate variation, and total setup cost, using a two-phase linear programming approach. In the first phase, the problem is solved using a max-min approach. The max-min solution not being efficient, in general, we propose a new model in the second phase to maximize a composite satisfaction degree at least as good as the degrees obtained by phase one. To show the effectiveness of... 

    Lower extremity kinematic analysis in male athletes with unilateral anterior cruciate reconstruction in a jump-landing task and its association with return to sport criteria

    , Article BMC Musculoskeletal Disorders ; Volume 20, Issue 1 , 2019 ; 14712474 (ISSN) Norouzi, S ; Esfandiarpour, F ; Mehdizadeh, S ; Yousefzadeh, N. K ; Parnianpour, M ; Sharif University of Technology
    BioMed Central Ltd  2019
    Background: Return to sport (RTS) criteria are widely being used to identify anterior cruciate ligament reconstructed (ACLR) athletes ready to return to sportive activity and reduce risk of ACL re-injury. However, studies show a high rate of ACL re-injury in athletes who passed RTS criteria. This indicates that the current RTS criteria might not be sufficient to determine return to sport time in ACLR athletes. Previous studies have reported a close association between altered lower limb kinematics and ACL re-injury. However, it is not clear how lower extremity kinematics differs between ACLR athletes who passed the RTS-criteria and who failed. This study compared lower extremity kinematics... 

    The power of environmental observatories for advancing multidisciplinary research, outreach, and decision support: the case of the minnesota river basin

    , Article Water Resources Research ; Volume 55, Issue 4 , 2019 , Pages 3576-3592 ; 00431397 (ISSN) Gran, K. B ; Dolph, C ; Baker, A ; Bevis, M ; Cho, S. J ; Czuba, J. A ; Dalzell, B ; Danesh Yazdi, M ; Hansen, A. T ; Kelly, S ; Lang, Z ; Schwenk, J ; Belmont, P ; Finlay, J. C ; Kumar, P ; Rabotyagov, S ; Roehrig, G ; Wilcock, P ; Foufoula Georgiou, E ; Sharif University of Technology
    Blackwell Publishing Ltd  2019
    Observatory-scale data collection efforts allow unprecedented opportunities for integrative, multidisciplinary investigations in large, complex watersheds, which can affect management decisions and policy. Through the National Science Foundation-funded REACH (REsilience under Accelerated CHange) project, in collaboration with the Intensively Managed Landscapes-Critical Zone Observatory, we have collected a series of multidisciplinary data sets throughout the Minnesota River Basin in south-central Minnesota, USA, a 43,400-km2 tributary to the Upper Mississippi River. Postglacial incision within the Minnesota River valley created an erosional landscape highly responsive to hydrologic change,... 

    A conflict resolution method for waste load reallocation in river systems

    , Article International Journal of Environmental Science and Technology ; Volume 16, Issue 1 , 2019 , Pages 79-88 ; 17351472 (ISSN) Aghasian, K ; Moridi, A ; Mirbagheri, A ; Abbaspour, M ; Sharif University of Technology
    Center for Environmental and Energy Research and Studies  2019
    Various urban, industrial, and agricultural pollutions discharge more than river self-purification potential damages river ecosystem and increases water treatment costs. As different decision-makers and stakeholders are involved in the water quality management in river systems, a new bankruptcy form of the game theory is used to resolve the existing conflict of interests related to waste load allocation in downstream river. The river restoration potential can allocate to the conflicting parties with respect to their claims, by using bankruptcy solution methods. In this research, dischargeable pollution loads to Karun River are determined by pollution sources in various scenarios using... 

    How to quantify sustainable development: A risk-based approach to water quality management

    , Article Environmental Management ; Volume 41, Issue 2 , 2008 , Pages 200-220 ; 0364152X (ISSN) Sarang, A ; Vahedi, A ; Shamsai, A ; Sharif University of Technology
    Since the term was coined in the Brundtland report in 1987, the issue of sustainable development has been challenged in terms of quantification. Different policy options may lend themselves more or less to the underlying principles of sustainability, but no analytical tools are available for a more in-depth assessment of the degree of sustainability. Overall, there are two major schools of thought employing the sustainability concept in managerial decisions: those of measuring and those of monitoring. Measurement of relative sustainability is the key issue in bridging the gap between theory and practice of sustainability of water resources systems. The objective of this study is to develop a... 

    Combination of multiple classifiers with fuzzy integral method for classifying the EEG signals in brain-computer interface

    , Article ICBPE 2006 - 2006 International Conference on Biomedical and Pharmaceutical Engineering, Singapore, 11 December 2006 through 14 December 2006 ; 2006 , Pages 157-161 ; 8190426249 (ISBN); 9788190426244 (ISBN) Shoaie, Z ; Esmaeeli, M ; Shouraki, S. B ; Sharif University of Technology
    In this paper we study the effectiveness of using multiple classifier combination for EEG signal classification aiming to obtain more accurate results than it possible from each of the constituent classifiers. The developed system employs two linear classifiers (SVM,LDA) fused at the abstract and measurement levels for integrating information to reach a collective decision. For making decision, the majority voting scheme has been used. While at the measurement level, two types of combination methods have been investigated: one used fixed combination rules that don't require prior training and a trainable combination method. For the second type, the fuzzy integral method was used. The... 

    Discrimination between Alzheimer's disease and control group in MR-images based on texture analysis using artificial neural network

    , Article ICBPE 2006 - 2006 International Conference on Biomedical and Pharmaceutical Engineering, Singapore, 11 December 2006 through 14 December 2006 ; 2006 , Pages 79-83 ; 8190426249 (ISBN); 9788190426244 (ISBN) Torabi, M ; Ardekani, R. D ; Fatemizadeh, E ; Sharif University of Technology
    In this study, we have proposed a novel method investigates MR-Images for normal and abnormal brains which effected by Alzheimer's Disease (AD) to extract 336 number of different features based on texture analysis. Before applying this algorithm, we have to use a registration method because of variety in size of normal and abnormal images. Consequently, the output of Texture Analysis System (TAS) is a vector containing 336 elements that are features extracted from texture. This vector is considered as the input of the Artificial Neural Network (ANN) which is feed-forward one. The features extracted from the Gray-level Co-occurrence Matrix (GLCM) have been interpreted and compared with normal... 

    The tolerance level of the ecosystem as a limited constrain in the development planning

    , Article Ecological Indicators ; Volume 132 , 2021 ; 1470160X (ISSN) Bararzadeh Ledari, M ; Saboohi, Y ; Azamian, S ; Sharif University of Technology
    Elsevier B.V  2021
    There are several methods for assessing ecosystem tolerance level, each method is defined according to the target of the ecosystem development. This paper seeks a way to plan for the development of the existing ecosystems modified for human activities. For this purpose, two methods have been applied to assess the effects of local development on the local ecosystem tailored to the different demands. Thus, after gathering data in a coastal region all technologies being capable to be applied in this region regarding ecotourism development (population growth) were determined. Via different indicators, the quality of the ecosystem was evaluated. The Ecosystem Quality Index (EQI) and Technique for... 

    An implementation of a CBIR system based on SVM learning scheme

    , Article Journal of Medical Engineering and Technology ; Volume 37, Issue 1 , 2013 , Pages 43-47 ; 03091902 (ISSN) Tarjoman, M ; Fatemizadeh, E ; Badie, K ; Sharif University of Technology
    Content-based image retrieval (CBIR) has been one of the most active areas of research. The retrieval principle of CBIR systems is based on visual features such as colour, texture and shape or the semantic meaning of the images. A CBIR system can be used to locate medical images in large databases. This paper presents a CBIR system for retrieving digital human brain magnetic resonance images (MRI) based on textural features and the support vector machine (SVM) learning method. This system can retrieve similar images from the database in two groups: normal and tumoural. This research uses the knowledge of the CBIR approach to the application of medical decision support and discrimination... 

    An interactive cbir system based on anfis learning scheme for human brain magnetic resonance images retrieval

    , Article Biomedical Engineering - Applications, Basis and Communications ; Volume 24, Issue 1 , 2012 , Pages 27-36 ; 10162372 (ISSN) Tarjoman, M ; Fatemizadeh, E ; Badie, K ; Sharif University of Technology
    Content-based image retrieval (CBIR) has turned into an important and active potential research field with the advance of multimedia and imaging technology. It makes use of image features, such as color, texture and shape, to index images with minimal human intervention. A CBIR system can be used to locate medical images in large databases. In this paper we propose a CBIR system which describes the methodology for retrieving digital human brain magnetic resonance images (MRI) based on textural features and the Adaptive neuro-fuzzy inference system (ANFIS) learning to retrieve similar images from database in two categories: normal and tumoral. A fuzzy classifier has been used, because of the... 

    Cost and entropy generation minimization of a cross-flow plate fin heat exchanger using multi-objective genetic algorithm

    , Article Journal of Heat Transfer ; Volume 133, Issue 2 , Nov , 2011 ; 00221481 (ISSN) Ahmadi, P ; Hajabdollahi, H ; Dincer, I ; Sharif University of Technology
    In the present work, a thermal modeling is conducted for optimal design of compact heat exchangers in order to minimize cost and entropy generation. In this regard, an εNTU method is applied for estimation of the heat exchanger pressure drop, as well as effectiveness. Fin pitch, fin height, fin offset length, cold stream flow length, no-flow length, and hot stream flow length are considered as six decision variables. Fast and elitist nondominated sorting genetic algorithm (i.e., nondominated sorting genetic algorithm II) is applied to minimize the entropy generation units and the total annual cost (sum of initial investment and operating and maintenance costs) simultaneously. The results for... 

    Optimal policy of energy innovation in developing countries: Development of solar PV in Iran

    , Article Energy Policy ; Volume 37, Issue 3 , 2009 , Pages 1116-1127 ; 03014215 (ISSN) Shafiei, E ; Saboohi, Y ; Ghofrani, M.B ; Sharif University of Technology
    The purpose of this study is to apply managerial economics and methods of decision analysis to study the optimal pattern of innovation activities for development of new energy technologies in developing countries. For this purpose, a model of energy research and development (R&D) planning is developed and it is then linked to a bottom-up energy-systems model. The set of interlinked models provide a comprehensive analytical tool for assessment of energy technologies and innovation planning taking into account the specific conditions of developing countries. An energy-system model is used as a tool for the assessment and prioritization of new energy technologies. Based on the results of the...