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    Design and Fabrication of Buck-Boost DC-DC Converter and Linear Regulator With Digitally-Tunable Output Voltage in 0.18µm-HV BCD CMOS Process

    , M.Sc. Thesis Sharif University of Technology Kargaran, Masoud (Author) ; Medi, Ali (Supervisor)
    Abstract
    In this project, an inverting Buck-Boost converter with two negative linear regulator is designed, implemented and measured in CMOS 0.18μm-HV BCD technology. Input voltage of Buck-Boost converter can vary from +15V to +28 and output voltage is digitally adjustable from -1V to -10V. Maximum output current of the converter is 300mA. A current mode controller and a lag compensator is used to control the converter. A high speed highside current sensor is designed and used in current mode controller. Sampled current of the current sensor is also used in a current limit circuitary to limit the maximum current of highside switch. Two negative linear regulators are placed at the output of the... 

    Design and Implementation of a High-Speed, High-Efficiency Integrated DC–DC Converter

    , Ph.D. Dissertation Sharif University of Technology Kargaran, Masoud (Author) ; Medi, Ali (Supervisor)
    Abstract
    Design and Implementation of a High-Speed, High-Efficiency Integrated DC–DC ConverterWith the rapid development of portable electronic devices, systems-on-chip (SoCs), and high-density integrated circuits, the design and development of voltage regulators and DC–DC converters with high response speed, high efficiency, and minimal area occupation have become increasingly important. In such systems, digital or analog loads with fast current variation rates impose significant stress on power management units (PMUs), and if the regulator exhibits slow dynamic performance, voltage fluctuations may disrupt the proper operation of the entire system. In particular, in applications such as Dynamic... 

    Self-Powered soil moisture monitoring sensor using a picoampere quiescent current wake-up circuit

    , Article IEEE Transactions on Instrumentation and Measurement ; Volume 69, Issue 9 , 2020 , Pages 6613-6620 Kargaran, M ; Habibi, M ; Magierowski, S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2020
    Abstract
    Low-power wireless stand-alone sensors that can operate without any wiring have received significant attention in sensor network applications. These devices harvest environmental energy resources to supply their power and transfer their collected data using wireless RF links. In many instances, the power supplied from the environment is far less than the power required by the sensor device. In this case, the main solution is to accumulate energy on a storage element, and when enough energy is stored, the sensor node is instantaneously activated using an undervoltage lockout (UVLO) circuit. During this short time burst, the sensor performs the required acquisition, transmits the results, and... 

    Study of Net Current of Particles in 2D Pulsated Potential Landscape

    , M.Sc. Thesis Sharif University of Technology Kargaran, Amir (Author) ; Ejtehadi, Mohammad Reza (Supervisor)
    Abstract
    In systems possessing spatial or dynamical symmetry breaking, Brownian motion combined with unbiased external input signals, deterministic and random alike, can assist directed motion of particles at nanoscale. “Brownian motors” are devices by whi thermally or extrinsically activated processes are controlled and used to generate directed motion in space. Rectification devices involving asymmetric substrates are termed ratets and if the potential priodically turns on and off in time, it is called “Pulsated Ratet.“ In this resear net current of particles in 2D pulsated asymmetric potential landscapes is surveyed theoretically and by
    Monte Carlo method simulation  

    An optimum transient response synchronous buck converter employing a novel analog multiplier controller

    , Article IEEE Transactions on Power Electronics ; Volume: 40, Issue: 9 , 2024 , 12112 - 12122 ; 08858993 (ISSN) Kargaran, M ; Besharati Rad, A ; Medi, A ; Sharif University of Technology
    IEEE  2024
    Abstract
    An ultra-fast step response synchronous buck converter has been developed for battery-powered and hand-held electronic applications. The proposed converter has an impressive settling time of only two clock periods and a 1.8A output current capability. This fast step response makes the proposed converter an ideal choice for dynamic voltage scaling technique in the mentioned applications. The proposed design utilizes an analog multiplier controller (AMC), which provides an optimum disturbance-damping mechanism to remove any output voltage error in just two clock periods. In addition, the synchronization feature of the AMC buck converter eliminates the electromagnetic interference concern in... 

    Improving the Design of Menus in User Interfaces

    , M.Sc. Thesis Sharif University of Technology Kargaran Khouzani, Amir Hossein (Author) ; Heydarnoori, Abbas (Supervisor)
    Abstract
    The design and development process of menu systems has always been a focus of researchers and engineers in the fields of software engineering and human-computer interaction. Considering the large and complex nature of the design space, it is nec- essary to provide automatic methods that aid designers during the design process. In this study, natural language processing is used to investigate the semantic relationship between menu system commands. Users expect related commands to be conveniently located next to each other, and a properly designed interface satisfies this need. As a result of this research, a fast-text-based model is developed that uses the data of past menu systems. In a... 

    GIRT-data: sampling github issue report templates

    , Article Proceedings - 2023 IEEE/ACM 20th International Conference on Mining Software Repositories, MSR 2023 ; 2023 , Pages 104-108 ; 979-835031184-6 (ISBN) Nikeghbal, N ; Hossein Kargaran, A ; Heydarnoori, A ; Schutze, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2023
    Abstract
    GitHub's issue reports provide developers with valuable information that is essential to the evolution of a software development project. Contributors can use these reports to perform software engineering tasks like submitting bugs, requesting features, and collaborating on ideas. In the initial versions of issue reports, there was no standard way of using them. As a result, the quality of issue reports varied widely. To improve the quality of issue reports, GitHub introduced issue report templates (IRTs), which pre-fill issue descriptions when a new issue is opened. An IRT usually contains greeting contributors, describing project guidelines, and collecting relevant information. However,... 

    Local model of a scientific collaboration in physics network compared with the global model

    , Article Physica A: Statistical Mechanics and its Applications ; Volume 389, Issue 23 , 2010 , Pages 5530-5537 ; 03784371 (ISSN) Roohi, A. A ; Shirazi, A. H ; Kargaran, A ; Jafari, G. R ; Sharif University of Technology
    2010
    Abstract
    We have constructed a collaboration network for physicists based in Iran working in different disciplines. By discussing properties like collaborators per author, shortest path, betweenness, and the concept of power in networks for this local model, and comparing with the global model, we understand how a developing country in the Middle East is contributing to the scientific growth in the world statistically. In this comparison, we found some properties of the local model which were not in accordance with the standard global society of science, which should be considered in developing the future policies. Our results show significant differences in factors like the degree and the diameter... 

    Quartic balance theory: Global minimum with imbalanced triangles

    , Article Physical Review E ; Volume 102, Issue 1 , 2020 Kargaran, A ; Ebrahimi, M ; Riazi, M ; Hosseiny, A ; Jafari, G. R ; Sharif University of Technology
    American Physical Society  2020
    Abstract
    Balance theory proposed by Heider for the first time modeled triplet interaction in a signed network, stating that relationships between two people, friendship or enmity, is dependent on a third person. The Hamiltonian of this model has an implicit assumption that all triads are independent, meaning that the type of each triad, being balanced or imbalanced, determined apart from the state of other triads. This independence forces the network to have completely balanced final states. However, there exists evidence indicating that real networks are partially balanced, raising the question of what is the mechanism preventing the system to be perfectly balanced. Our suggestion is to consider a... 

    Adaptation through Crowdsourcing in Disaster Management: A Complexity Theory Perspective

    , Ph.D. Dissertation Sharif University of Technology Darivandi Shoushtari, Kosar (Author) ; Masoud Talebian (Supervisor) ; Shadnam, Masoud (Supervisor)
    Abstract
    The increasing frequency and intensity of disasters worldwide are giving rise to increasingly complex situations. Affected communities often struggle to respond effectively and rapidly using only their existing resources and infrastructure, including formal emergency response systems. In this context, voluntary efforts by citizen volunteers play an important role in enhancing communities’ adaptive capacity and resilience. Nevertheless, the considerable potential of volunteer-led disaster response is undermined by challenges related to coordination and organizing. Realizing this potential requires appropriate organizing solutions. This dissertation explores various approaches to organizing... 

    Long Term Effective Factors on House Price of Metropolises of Iran

    , M.Sc. Thesis Sharif University of Technology Moeeni, Safoura (Author) ; Nili, Masoud (Supervisor)
    Abstract
    The notable share of housing sector in GDP (approximately five percent) shows this sector’s relation with macroeconomic activities. On the other hand, House as an asset leads housing sector to be affected by monetary and fiscal variables. A dynamic panel data was used in this study to evaluate the relations between housing sector and some macroeconomic variables in metropolises of Iran. As results show, in long term growth of liquidity, GDP per capita and sharp ratio have positive effects, and land per capita has negative effect on housing price in metropolises of Iran. Price increases have not been equal in different cities. Inequality of land price between metropolises and between... 

    Estimating an Index of Iran’s Informal Economy in 1350-1386 With Concentration on the Impact of Government’s Intervention by EMIMIC Model (The Multiple Indicators-Multiple Causes Model and Error-Correction Model)

    , M.Sc. Thesis Sharif University of Technology Khandan, Abbas (Author) ; Nili, Masoud (Supervisor)
    Abstract
    In this research, an Index of Iran informal economy in response to the government interventions in credit, labor and product markets is stimated by EMIMIC model. To do this, first these interventions are measured using principal components analysis. In the model, the variables GDP and employment are used as indicators and taxation rates, government distortions in credit, labor and product markets, government expenditure, per capita income, unemployment and inflation as causes of the informal economy. We conclude these government interventions have affected Iran informal economy and their influence is more than indirect interventions influence such as taxation. The estimated index of Iran... 

    Water Quality Modeling of Urban Streams

    , M.Sc. Thesis Sharif University of Technology Soltani, Maryam (Author) ; Tajrishy, Masoud (Supervisor)
    Abstract
    With altering natural state and increasing impervious surfaces, traditional urbanization leads to deteriorating the environment and water catchments. During the years most efforts in order to control the urban runoff outflow, have been focused on quantity; and awareness about improving water quality has been raised just in the last few years and, which emphasizes on pollution source control. Standard water quality sampling methods are time consuming, expensive and because of sampling in broad geographic areas, difficult; however modeling is a more efficient way in assessing water quality and as worries about non-point source pollution grows, different kinds of models have been used to... 

    The Political Economy Aspects of the Redistributive Role of Government in a General Equilibrium Micro-founded Macro Model

    , M.Sc. Thesis Sharif University of Technology Zakeri, Hassan (Author) ; Nili, Masoud (Supervisor)
    Abstract
    The role of government in economy has been a controversial subject in economics. Lately, there has been some fundamental change in evaluating this subject. One could mention two of these as 1) realizing the importance of micro-founded macro model for evaluating policy, and 2) taking into consideration the rent-seeking behavior of politicians. In this research, a general equilibrium in a micro-founded macro model will be discussed and then in political economics framework, the effect of government on this equilibrium will be investigated. Only the redistribution role of government has been considered. First, the model in which a benevolent government is seeking optimal policy is Discussed.... 

    Measurement of Gini Coefficients by Means of Household’s Special CPI in Iran(1984-2005)

    , M.Sc. Thesis Sharif University of Technology Ghasemi, Mojtaba (Author) ; Nili, Masoud (Supervisor)
    Abstract
    Gini coefficient is the most prevalent index for the measurement of inequality and is usually extracted by means of nominal variables based on income or expenditures of households. In this study we have extracted more accurate Gini coefficients. By using the raw data of Households Budget Survey (HBS) and STATA software, a special CPI for each household of the sample is extracted. Subsequently nominal expenditures are deflated by these special CPIs, and at last, Gini coefficients are extracted from real expenditures. Our findings indicate that in recent years, extracted Gini coefficients are remarkably higher than prevailing ones.
     

    Parametric Evaluation of the Y- Shaped Bracing Frame and Introducing a New Method for Design

    , M.Sc. Thesis Sharif University of Technology Sedaghati, Parshan (Author) ; Mofid, Masoud (Supervisor)
    Abstract
    This paper investigates the behavior of the Y-shaped bracing system. Because of the special type of eccentricity in this system, the behavior of the frame is strongly dependent on the geometrical changes of the braces. So that even in the elastic region, it shows the geometrically nonlinear behavior. The amount of eccentricity is very effective on the nonlinear behavior of the frame. Also the ratio of cross sections of the bracing members has a very important impact on the expected performance of the frame. The results show that this system tolerates large displacements, and can act like a base isolation system. Firstly, using a two-dimensional accurate modeling related to the geometrical... 

    Assessment of Seismic Behavior Factor of Irregular Midrise Steel Structure

    , M.Sc. Thesis Sharif University of Technology Baghi, Alireza (Author) ; Mofid, Masoud (Supervisor)
    Abstract
    The Overstrength, Ductility and the Response Modification Factor (R) for 70 steel X-braced , Inverted-V-Braced and Offcenter Bracing System frames were evaluated by performing pushover analysis of model structure with various stories (3,6,9,12&15 story) and span length (4,6&8 meter). Some result were compared with those from nonlinear dynamic analysis. According to the analysis result the R factors obtained from nonlinear dynamic analysis are 15% more than obtained from pushover analysis and R factors computed from pushover analysis were generally smaller than the values given in the design codes. R factors in Irregular structure in height are about 90% of R values in regular structure in... 

    Synthesis of γ-Fe2O3 Nanoparticles by Gelatin Mediator and Synthesis of γ-Fe2O3/SiO2/PCA/Ag-NPs Nanostructure Drug Delivery System

    , M.Sc. Thesis Sharif University of Technology Masoud, Nazila (Author) ; Pourjavadi, Ali (Supervisor)
    Abstract
    Maghemite (γ-Fe2O3) nanoparticles were produced after high temperature oxidation of gelatin-Fe3O4 nanocomposite, obtained from a common coprecipitation process of Fe2+ and Fe3+ ions in an alkaline medium in the presence of a gelatin protein as an effective mediator. Size, shape, surface morphology and magnetic properties of the prepared γ-Fe2O3 nanoparticles were characterized using XRD, FTIR, TEM, SEM and VSM data. The results revealed that primary, gelatin-Fe3O4 nanocomposite had been formed and next, the gelatin decomposition in furnace produced a spinel structure of γ-Fe2O3. The effects of furnace temperature and time of heating together with the amount of gelatin on the produced... 

    On The Behavior of Low-Rise, Irregular, Dual Structures

    , M.Sc. Thesis Sharif University of Technology Khazaei, Siamak (Author) ; Mofid, Masoud (Supervisor)
    Abstract
    The Response modification factor R represents the behavior of the structure such as ductility, overstrength and the inherent redundancy. This factor shall be defined according to the type of lateral force resisting system. However, there are some complexities and/or uncertainties in codes related to the R factor according to the height, form of irregularities and structural systems. Therefore, from the scientific point of view as well as reliability, it is very clear that the R factor cannot be similar for all kinds of structures, categorized as a specific group. In this investigation, assuming a low-rise, vertically irregular structure with a heliport which has a dual structural system... 

    Modeling Phosphorous Movement in Watersheds with SWAT (Case Study: Kan Watershed)

    , M.Sc. Thesis Sharif University of Technology Delkash, Majid (Author) ; Tajrishy, Masoud (Supervisor)
    Abstract
    Maintaining the quality of water is of paramount importance for lakes with tourist attraction capacity. Inaccurate prediction of the quality state of lake in design phase may lead to some trouble in future. Kan River known as the main source of water feeding for the urban lake located in the north of Chitgar park passes through various villages and restaurants discharging nutrients via runoff and wastewater in the aforementioned river. Previous investigations reveal that phosphorous plays a central role in the water quality of this river and the associated downstream lake. In this research, Kan watershed,located in in the north-west of Tehran, was simulated. Considering the "Total Maximum...