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    Optimizing the Total Cost of Inventory Control System in Integrated Multi-Echelon Supply Chain With Time-sensitive Deteriorating Rates

    , M.Sc. Thesis Sharif University of Technology Mohammadi, Vahid (Author) ; hajji, Rasool (Supervisor)
    In this paper, we consider a three-echelon supply chain consisting of a producer, a distributor and a retailer. Generally each echelon tends to minimize his own inventory costs. On the other hand, competitive environment of business market, force companies to develop strategic alliances. In order to boost their partnership, separated echelons must integrate their policies, so that the total cost of the system be minimized. The model, extends the research of Wang et al.(2011) by changing the No shortage assumption into backlog shortage model.
    This study assumes different deterioration rates among different echelons, and deterioration rates are time-sensitive, which is very helpful in... 

    Incorporating Three Echelon Location, Routing and Inventory Decisions in Supply Chain Network Design with Heterogeneous Vehicle

    , M.Sc. Thesis Sharif University of Technology Shakeri, Mohammad Hesam (Author) ; Shadrokh, Shahram (Supervisor)
    A key driver of the overall productivity and profitability of a supply chain is its distribution network which can be used to achieve a variety of the supply chain objectives ranging from low cost to high responsiveness. Designing a distribution network consists of three subproblems: location–allocation problem, vehicle routing problem, and inventory control problem. Because of high dependency among these problems, in the literature there are several papers integrating two of the above problems: location–routing problems, inventory–routing problems, and location–inventory problems.
    The three echelon location routing inventori problem (LRIP) is raised by the design of transportation... 

    A Location-Routing-Inventory Problem with Cross-Docking and Split Delivery

    , M.Sc. Thesis Sharif University of Technology Faraji, Mahla (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)
    This paper studies a multi-product, multi-period location- routing- inventory problem in a three-level supply chain including suppliers, cross-docks and customers. Each cross-dock could be supplied by more than one supplier and each customer could be supplied by more than one cross-dock. In the first phase we find the best locations for the cross-dock and allocate them to customers and suppliers by considering inventory costs. . Then, in the second phase Products are distributed from cross-docks towards customers using Heterogeneous vehicles. In this article the option for split delivery is enabled and furthermore, backlogging is allowable for each customer. The model presented in this... 

    Design and analysis of broadband darlington amplifiers with bandwidth enhancement in GaAs pHEMT technology

    , Article IEEE Transactions on Microwave Theory and Techniques ; Volume 62, Issue 8 , August , 2014 , Pages 1705-1715 ; ISSN: 00189480 Nikandish, G ; Medi, A ; Sharif University of Technology
    This paper presents a bandwidth enhancement technique for broadband Darlington amplifiers. A detailed analysis of the high-frequency performance of the Darlington amplifier and the effect of bandwidth enhancement is provided. A design procedure is also given for broadband feedback Darlington amplifiers with bandwidth enhancement and gain flattening. A single- and a three-stage feedback amplifier with the proposed improvements are designed and implemented in a 0.25-μm Al-GaAs-InGaAs pHEMT technology. The single-stage amplifier provides 6 ± 0.4 dB of small-signal gain in the frequency band of 1-30 GHz. The three-stage amplifier features 17.8 ± 0.8 dB of small-signal gain in the frequency band... 

    Lesson learned knowledge in project management

    , Article Science and Information Conference, SAI 2015, 28 July 2015 through 30 July 2015 ; July , 2015 , Pages 949-953 ; 9781479985470 (ISBN) Sepehri, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Every project is temporary and unique in nature. However, knowledge and lessons learned in projects may be used in other projects to improve the project management services. A learned lesson comes from past and current projects, captured through well-defined organizational processes. It aims to capture an essence of an experience which may be utilized to modify the project processes, or the situations for which that lesson applies. Although lessons learned is used in many industries and is an essential part of Project Management Body of Knowledge, no effective process has been defined to capture, validate, and reuse projects' lessons learned. A three stage system was developed and used to... 

    Feeder growth: a new method for automatic optimal feeder design in gravity casting processes

    , Article Structural and Multidisciplinary Optimization ; Volume 39, Issue 5 , 2009 , Pages 519-530 ; 1615147X (ISSN) Tavakoli, R ; Davami, P ; Sharif University of Technology
    The optimal feeder design in gravity casting processes is considered. The design problem is formulated as an additive, growth-like, evolutionary topology optimization problem. The initial design of the presented method is a casting part which is placed in a suitable environmental mould box. The method is composed of three stages: determining the feeder-neck connection point on the casting surface, constructing the feeder-neck and the feeder growth. During the growth stage, the feeder topology is changed gradually until satisfying some predefined criteria. The design of multiple feeders is also considered in this work. In the presented method, feeders are designed in a descending order of... 

    Two-dimensional clustering of nanoparticles on the surface of cellulose fibers

    , Article Journal of Physical Chemistry C ; Volume 113, Issue 28 , 2009 , Pages 12022-12027 ; 19327447 (ISSN) Khajeh Aminian, M ; Taghavinia, N ; Irajizad, A ; Mahdavi, M ; Ye, J ; Chavoshi, M ; Vashaei, Z ; Sharif University of Technology
    Density of surface charges of cellulose fibers and -potential of TiO2 nanoparticles in the solution were measured and controlled by pH. The adsorption and clustering of TiO2 nanoparticles on the surface of cellulose fibers were studied using scanning electron microscopy (SEM) and a scale in different situations of repulsion and attraction between the particles and surface. The experiments show formation of two-dimensional clusters of nanoparticles on the surface. Weight measurement of the adsorbed particles and clusters via the adsorption time results in that there are three stages containing nucleation, two-dimensional growth and saturation for clustering of nanoparticles on the surface.... 

    Step-by-step improvement of mixed-matrix nanofiber membrane with functionalized graphene oxide for desalination via air-gap membrane distillation

    , Article Separation and Purification Technology ; Volume 256 , 2021 ; 13835866 (ISSN) Fouladivanda, M ; Karimi Sabet, J ; Abbasi, F ; Moosavian, M. A ; Sharif University of Technology
    Elsevier B.V  2021
    A straightforward three-stage method was applied to fabricate a super-hydrophobic mixed-matrix nanofiber membrane using the electrospinning method for desalination purpose. First, a hydrothermal technique was applied to synthesize a super-hydrophobic nano-sheet, called octadecylamine-reduced graphene oxide (ODA-rGO) with a water contact angle of 162°, which was then added to PVDF-HFP dope solution. After, 0.005 wt% LiCl was added to the dope solution to decrease the mean pore size by increasing solution conductivity. Moreover, some membranes were hot-pressed to improve liquid entry pressure (LEP). Eventually, a top-quality nanofiber membrane was synthesized using 0.1 wt% ODA-rGO and 0.005... 

    Location Routing Inventory Problem Using Robust Optimization Approach

    , M.Sc. Thesis Sharif University of Technology Heyhat, Shaghayegh (Author) ; Akbari Jokar, Mohammad Reza (Supervisor)
    This thesis studies a multi–period location–routing–inventory problem in a three layer supply chain including manufacturers, distribution centers and customers with consideration of capacity constraint in distribution centers and heterogeneous fleet of vehicles. Moreover, the demand parameter is considered uncertain and there is no available information about distribution function of demand parameter. For handling problem uncertainty, Bertsimas and sim robust optimization approach is used and a mixed integer programming is presented for both deterministic problem and robust counterpart problem. Then simulated annealing and genetic algorithms are proposed to solve the model.... 

    Identifying and Ranking Supply Chain Risk Factors and Calculating Reliability in 3 Level Supply Chain

    , M.Sc. Thesis Sharif University of Technology Kardar Rostami, Reza (Author) ; Eshraghnia Jahromi, Abdolhamid (Supervisor)
    Since 1990, supply chains get affected by business environment changes and become more vulnerable. Changes such as globalization, decrease of inventory levels, out sourcing, etc. in this thesis after reviewing some paper, researches are categorized in 8 group. Then 30 risk factor identified from this papers. Because of basic differences in industries and different importance of risk factors in them, a case was studied in one industrial area and risk factors was evaluated in a two-step evaluation. Eventually some advices presented for increasing reliability for that case  

    Analysis of Parameters Affecting the Behavior of Frequency Selective Devices and their Scaling to Nano Regimes

    , M.Sc. Thesis Sharif University of Technology Sadeghi, Mohammad Naser (Author) ; Rashidian, Bijan (Supervisor)
    In this project, different types of optical frequency selector devices are compared with each other and the factors limiting their behavior (losses, throughput, quality factor, etc.) are precisely analyzed. Change this behavior in near-field and far-field scales as well as the behavior of these devices in nano-dimensions are analyzed. Also, the main theoretical and technological limitations of different types of optical filters in far-field and near-field regimes are compared. In the following, the scaling behavior of different filter families in passing to nanometric dimensions is investigated and finally the limitations of the possibility of making the selected sample are analyzed. For... 

    An efficient genetic algorithm to maximize net present value of project payments under inflation and bonus-penalty policy in resource investment problem

    , Article Advances in Engineering Software ; Volume 41, Issue 7-8 , July–August , 2010 , Pages 1023-1030 ; 09659978 (ISSN) Shahsavar, M ; Akhavan Niaki, S. T ; Najafi, A. A ; Sharif University of Technology
    In order to develop a more realistic resource-constrained project-scheduling model that is applicable to real-world projects, in this paper, the resource investment problem with discounted cash flows and generalized precedence relations is investigated under inflation factor such that a bonus-penalty structure at the deadline of the project is imposed to force the project not to be finished beyond the deadline. The goal is to find activity schedules and resource requirement levels that maximize the net present value of the project cash flows. The problem is first mathematically modeled. Then, a genetic algorithm (GA) is designed using a new three-stage process that utilizes design of... 

    Adsorptive removal of petroleum hydrocarbons from aqueous solutions by novel zinc oxide nanoparticles grafted with polymers

    , Article Petroleum Science and Technology ; Volume 34, Issue 8 , 2016 , Pages 778-784 ; 10916466 (ISSN) Salehi, B ; Hasani, A. H ; Ahmad Panahi, H ; Borghei, S. M ; Sharif University of Technology
    Taylor and Francis Inc 
    Zinc oxide nanoparticles were synthesized and modified by a three-stage method. Elemental analysis, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning and transmission electron microscopy, and Brunauer–Emmett–Teller method were applied to characterize the nanoparticles. These nanoparticles were evaluated for toluene adsorption from aqueous solutions as a representative of petroleum hydrocarbon removal. The optimum adsorption condition achieved at pH of 6 and contact time of 30 min. The adsorption isotherms were fitted to the Langmuir model. The measured adsorption capacity was 12.8 mg g−1. This study demonstrated that these nanoparticles could be used as an... 

    A trainable neural network ensemble for ECG beat classification

    , Article World Academy of Science, Engineering and Technology ; Volume 70 , 2010 , Pages 788-794 ; 2010376X (ISSN) Sajedin, A ; Zakernejad, S ; Faridi, S ; Javadi, M ; Ebrahimpour, R ; Sharif University of Technology
    This paper illustrates the use of a combined neural network model for classification of electrocardiogram (ECG) beats. We present a trainable neural network ensemble approach to develop customized electrocardiogram beat classifier in an effort to further improve the performance of ECG processing and to offer individualized health care. We process a three stage technique for detection of premature ventricular contraction (PVC) from normal beats and other heart diseases. This method includes a denoising, a feature extraction and a classification. At first we investigate the application of stationary wavelet transform (SWT) for noise reduction of the electrocardiogram (ECG) signals. Then...