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دسترسی آزاد مقاله
1 - A Near Optimal Approach in Choosing The Appropriate Physical Machines for Live Virtual Machines Migration in Cloud Computing
Seyedeh Roudabeh Hosseini Sepideh Adabi Reza TavoliMigration of Virtual Machine (VM) is a critical challenge in cloud computing. The process to move VMs or applications from one Physical Machine (PM) to another is known as VM migration. In VM migration several issues should be considered. One of the major issues in VM m چکیده کاملMigration of Virtual Machine (VM) is a critical challenge in cloud computing. The process to move VMs or applications from one Physical Machine (PM) to another is known as VM migration. In VM migration several issues should be considered. One of the major issues in VM migration problem is selecting an appropriate PM as a destination for a migrating VM. To face this issue, several approaches are proposed that focus on ranking potential destination PMs by addressing migration objectives. In this paper we propose a new hierarchal fuzzy logic system for ranking potential destination PMs for a migrating VM by considering following parameters: Performance efficiency, Communication cost between VMs, Power consumption, Workload, Temperature efficiency and Availability. Using hierarchal fuzzy logic systems which consider the mentioned six parameters which have great role in ranking of potential destination PMs for a migrating VM together, the accuracy of PMs ranking approach is increased, furthermore the number of fuzzy rules in the system are reduced, thereby reducing the computational time (which is critical in cloud environment). In our experiments, we compare our proposed approach that is named as (HFLSRPM: Hierarchal Fuzzy Logic Structure for Ranking potential destination PMs for a migrating VM) with AppAware algorithm in terms of communication cost and performance efficiency. The results demonstrate that by considering more effective parameters in the proposed PMs ranking approach, HFLSRPM outperforms AppAware algorithm. پرونده مقاله -
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2 - مکانیابی محلهای مناسب جهت دفن و راهبردهای مدیریت پسماندهای جامد در شهر شوشتر با استفاده ازGIS
احمد احمد پور محسن رنجبر سید عباس رجایی مرضیه همتی زادهتولید پسماند از جمله مشکلات مدیریت شهری است که امروزه به یکی از معضلات عمده شهرها تبدیل شده است که تاثیرات نامطلوب زیست محیطی در شهرها به جا میگذارد. در این پژوهش از سیستمهای اطلاعات جغرافیای به عنوان ابزاری کار آمد برای مکانیابی ومدیریت بهینه دفن مواد زاید شهری استف چکیده کاملتولید پسماند از جمله مشکلات مدیریت شهری است که امروزه به یکی از معضلات عمده شهرها تبدیل شده است که تاثیرات نامطلوب زیست محیطی در شهرها به جا میگذارد. در این پژوهش از سیستمهای اطلاعات جغرافیای به عنوان ابزاری کار آمد برای مکانیابی ومدیریت بهینه دفن مواد زاید شهری استفاده شده است. برای این منظور 20 لایه اطلاعاتی دخیل در امر مکان یابی دفن در محیط GIS تهیه و بر روی این لایه ها پردازش انجام شده و سپس با روش AHP ، وزن مناسب از طریق ماتریس مقایسه زوجی اعمال شده و به وسیله دو مدل منطق بولین ومنطق فازی لایه ها با هم تلفیق و تجزیه و تحلیل نهایی صورت گرفته ومناطق مناسب استخراج و به تحلیل نقاط انتخابی پرداخته شده است. نتایج بررسی نشان می دهد که از بین نقاط انتخاب شده یک محل دارای بالاترین اولویت برای دفن می باشد. دو نقطه به دلیل مناسب نبودن پی سنگ، بالا بودن سطح آب زیرزمینی، فرسایش پذیری بالا جهت دفن در اولویت قرار نگرفته اند. درنهایت محل های منتخب با محل فعلی مقایسه و سپس محل مناسب در شهرستان شوشتر تعیین وراهبردهای مدیریتی ارائه شده است. پرونده مقاله -
دسترسی آزاد مقاله
3 - Use of Fuzzy Numbers for Assessing Problem Solving Skills
Michael Gr‎.‎ Voskoglou‎ S. N. Mishra‎The importance of Problem Solving (PS) has been realized for such a long time that in a direct or indirect way affects our daily lives in many ways‎. ‎Assessment cases appear frequently for PS skills which involve a degree of uncertainty and (or) ambiguity& چکیده کامل‎The importance of Problem Solving (PS) has been realized for such a long time that in a direct or indirect way affects our daily lives in many ways‎. ‎Assessment cases appear frequently for PS skills which involve a degree of uncertainty and (or) ambiguity‎. ‎Fuzzy logic‎, ‎due to its nature of characterizing such cases with multiple values‎, ‎offers rich resources for dealing with them‎. ‎On the other hand‎, ‎Fuzzy Numbers (FNs) play a fundamental role in fuzzy mathematics‎, ‎analogous to the role played by the ordinary numbers in classical mathematics‎. ‎In the present paper we utilize the two simplest forms of them‎, ‎i.e‎. ‎the Triangular and Trapezoidal FNs‎, ‎together with the Centre of Gravity (COG) defuzzification technique as assessment tools for PS skills‎. ‎Our results are illustrated by three examples in which the assessment outcomes of FNs are validated through their comparison with the corresponding outcomes of assessment methods of the bi-valued and fuzzy logic already tested in author's earlier works‎. پرونده مقاله -
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4 - Fuzzy-GSA Based Control Approach for Developing Adaptive Cruise Control
M. BostanianAdaptive Cruise Control (ACC) controls vehicle speed and its distance to the proceeding vehicle in the same lane. In this paper a two-level control architecture is proposed to control both velocity and distance to the leading vehicle by taking advantage of fuzzy logic c چکیده کاملAdaptive Cruise Control (ACC) controls vehicle speed and its distance to the proceeding vehicle in the same lane. In this paper a two-level control architecture is proposed to control both velocity and distance to the leading vehicle by taking advantage of fuzzy logic control (FLC) approach. Then the control parameters were tuned by Gravitational Search Algorithm (GSA) to ensure achieving the fastest and most accurate control response. To evaluate performance of the proposed scheme, a speed profile was developed in simulation based test platform to measure performance of the proposed ACC in different maneuvers including some velocity tests and a distance control maneuver. The results revealed that the proposed approach had a stable and fast response which satisfied the requirements of an ACC. پرونده مقاله -
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5 - ارزیابی و شناسایی عوامل مؤثر بر وفاداری الکترونیکی در شرکت های ارائه دهنده خدمات الکترونیک با استفاده از تکنیک AHP فازی
Mahmood Khorasany Kiasari Leila Abdullah Zadeh Ramhormozi Fatemeh Rahmaniاینترنت یک بستر زیرساختی کسب وکار را برای تجارت الکترونیک فراهم کرده است بهطوریکه آمارها نشان دهنده روند رو به رشد خرید اینترنتی هستند. یکی از کاربردهای مورد توجه در فضای مجازی، تجارت الکترونیک است که موجب تحولی شگرف در روابط کسب وکار و مشتریان شده و سهم عمدهای از چکیده کاملاینترنت یک بستر زیرساختی کسب وکار را برای تجارت الکترونیک فراهم کرده است بهطوریکه آمارها نشان دهنده روند رو به رشد خرید اینترنتی هستند. یکی از کاربردهای مورد توجه در فضای مجازی، تجارت الکترونیک است که موجب تحولی شگرف در روابط کسب وکار و مشتریان شده و سهم عمدهای از تعاملات تجاری را به خود اختصاص داده است. از شیوههای نوین خرید که از مزایای گستردهای بهرهمند است، خرید اینترنتی است. در حال حاضر، بسیاری از خرید و فروشها در سراسر دنیا به این شیوه صورت میگیرند؛ ازاینرو، شناسایی صحیح نیازمندیهای مشتریان و خرید اینترنتی که انجام میدهند و پاسخ سریع به این نیازمندیها، کلید موفقیت تجاری و افزایش وفاداری مشتریان محسوب میشود. به منظور بررسی عوامل ایجاد وفاداری الکترونیکی برای سازمانهای ارائهدهنده خدمات خرید الکترونیکی، این تحقیق عوامل تأثیرگذار بر وفاداری مشتریان در خرید اینترنتی را شناسایی و بررسی مینماید و با تهیه پرسشنامه و با استفاده از فرآیند تصمیمگیری سلسله مراتبی فازی، وزن یا درجه اهمیت هریک از شاخصها را به دست میآورد و درنهایت آنها را رتبهبندی مینماید. با کمک نتایج بهدستآمده نشان خواهیم داد که کدام شاخص برای مشتریان، مهمترین عامل در ایجاد وفاداری الکترونیکی خواهد بود. پرونده مقاله -
دسترسی آزاد مقاله
6 - پهنهبندی مناطق مستعد وقوع بیماری فوزاریوم خوشه گندم با استفاده از مدل فازی و سیستم اطلاعات جغرافیایی در استان گلستان
هانیه نادری میرمسعود خیرخواه زرکش مسعود گودرزیدر این پژوهش، نقشه پهنه بندی مناطق مستعد وقوع بیماری بلایت فوزاریومی خوشه گندم مورد مطالعه قرار گرفت و مدل حاصل با نقشه پهنه بندی به دست آمده از گزارشات ایستگاه های تحقیقاتی گیاه پزشکی در استان گلستان با روش منطق فازی مقایسه شد. به این منظور میانگین معیار های رطوبت، دما چکیده کاملدر این پژوهش، نقشه پهنه بندی مناطق مستعد وقوع بیماری بلایت فوزاریومی خوشه گندم مورد مطالعه قرار گرفت و مدل حاصل با نقشه پهنه بندی به دست آمده از گزارشات ایستگاه های تحقیقاتی گیاه پزشکی در استان گلستان با روش منطق فازی مقایسه شد. به این منظور میانگین معیار های رطوبت، دما و بارش به مدت 45 روز در بازه زمانی رشد گندم پاییزه در مرحله 65 مقیاس زادوکس تعیین شد. با توجه به نظر بیماری شناسان گیاهی و زمان وقوع بیماری بلایت فوزاریومی خوشه گندم در استان گلستان، در بازه زمانی اواسط فروردین تا اواخر اردیبهشت ماه برای هر سه روز یک پهنه بندی تهیه شد. در مجموع 15 نقشه پهنه بندی ارایه و مناطق مستعد بیماری در این مدل مشخص گردید. پهنه بندی در چهار طبقه بی خطر (25%-0)، کم خطر (50%-26%)، خطرناک (75%-51%) و پرخطر (100%-76%) طبقه بندی شد و نتایج با استفاده از روش کاپا مورد اعتبار سنجی قرار گرفت. نتایج نشان داد که وقوع و شیوع بیماری از نیمه دوم فروردین تا اواسط اردیبهشت ماه در صورت قـرار داشتن خوشه ها در مرحله رشدی حسـاس به بیماری در مناطـق تعییـن شده با اعتبار سنجـی بیش از 76 درصد قابل پیش بینی است. این درحالی است که در این بازه زمانی علایم بیماری در خوشه ها قابل تشخیص نیستند. نتایج تحقیق حاضر، برای محققین و کارشناسان امر در زمینه پیش آگاهی و تصمیم گیری به موقع برای اعمال بهترین روش های مدیریت بیماری مفید خواهد بود پرونده مقاله -
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7 - Fuzzy-Logic Based Frequency Controller for Wind Farms Augmented With Energy Storage and PV Systems
Maryam Torabi Osguie Mehran Ansarin Masoud Solouki Abbas Nemati Yeganeh BakhshizadehTo improve the primary frequency response in future low-inertia hybrid power system a fuzzylogic based frequency controller (FFC) for wind farms augmented with energy storage systems(wind-storage system) and intelligent PV farms for the frequency stabilization is propos چکیده کاملTo improve the primary frequency response in future low-inertia hybrid power system a fuzzylogic based frequency controller (FFC) for wind farms augmented with energy storage systems(wind-storage system) and intelligent PV farms for the frequency stabilization is proposed inthis paper. Using system frequency deviations the proposed controller provides bidirectionalreal power injection and rate of change of frequency (RoCoF). Displacement of conventionalsynchronous generators by non-inertial units such as wind or solar generators will result inreduced-system inertia affecting under-frequency response. Frequency control is important toavoid equipment damage, load shedding, and possible blackouts. To improve the frequencyresponse of low-inertia power system Wind generators along with energy storage systems canbe used. Moreover, FFC ensures optimal use of energy from wind farms and storage units byeliminating the inflexible de-loading of wind energy and minimizing the required storagecapacity. The efficacy of the proposed FFC is verified by using the simulation results on thelow-inertia hybrid power system. پرونده مقاله -
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8 - A Fuzzy Logic Control System for Quadcopter by Human Voluntary-Physical Movements
Shayan Mesdaghi Mohamad Dosaranian-MoghadamIn recent years, many scientists in universities and research centers focused on quadcopters. One of the problems with quadcopters is the complexity of its manual control system. In a typical system, the user is the observer of robot in addition to controlling the radio چکیده کاملIn recent years, many scientists in universities and research centers focused on quadcopters. One of the problems with quadcopters is the complexity of its manual control system. In a typical system, the user is the observer of robot in addition to controlling the radio controller. In this paper, using a fuzzy logic algorithm, a robot control system for main and subsidiary movements by human head or wrist voluntary-physical movements is considered. In this case, without looking at control board the user can control the robot only with changing the head control voluntary or physical movements. Simulation results show that using fuzzy algorithm for determining the bending scale in different angles can decrease the human errors and processor computations. Also using fuzzy logic algorithm in the designed system the robot can track the user voluntary-physical movements optimally. In addition, the system output noises adjust due to involuntary user movements. پرونده مقاله -
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9 - A Hybrid Model for Assessing Student Mathematical Skills
Michael VoskoglouStudent assessment is a very important process in education, because it helps the instructor to determine student mistakes and to improve their performance by reforming his/her teaching plans. A hybrid assessment method using qualitative grades for evaluating student ma چکیده کاملStudent assessment is a very important process in education, because it helps the instructor to determine student mistakes and to improve their performance by reforming his/her teaching plans. A hybrid assessment method using qualitative grades for evaluating student mathematical skills is presented in this work. The paper starts with the mathematical background which is necessary for the understanding of its contents. This includes basic information about fuzzy, neutrosophic and soft sets, and about grey numbers. It also includes a description of the use of the center of gravity (COG) defuzzification technique for assessing a student group’s quality performance. The COG technique is compared with the classical method of calculating the GP A index. The hybrid assessment method, which is based on all the previous concepts and processes, is developed next and the article closes with the final conclusion and some recommendations for future research. پرونده مقاله -
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10 - بررسی و پتانسیلیابی خطر زمین لغزش با استفاده از مدل منطق فازی در حوضه آبریز کهمان استان لرستان
داریوش ابوالفتحی صیاد اصغری سراسکانرود احسان قلعهزمین لغزش به عنوان یکی از مخاطرات طبیعی هر ساله منجر به خسارات زیادی میشود. حوضه آبریز کهمان با دارا بودن ویژگیهای کوهستانی و شرایط طبیعی مختلف دارای استعداد بالقوه زمین لغزش است. هدف از این پژوهش بررسی خطر زمین لغزش با استفاده از مدل منطق فازی در حوضه کهمان استان لرس چکیده کاملزمین لغزش به عنوان یکی از مخاطرات طبیعی هر ساله منجر به خسارات زیادی میشود. حوضه آبریز کهمان با دارا بودن ویژگیهای کوهستانی و شرایط طبیعی مختلف دارای استعداد بالقوه زمین لغزش است. هدف از این پژوهش بررسی خطر زمین لغزش با استفاده از مدل منطق فازی در حوضه کهمان استان لرستان میباشد. در این مطالعه ابتدا پارامترهای مؤثر در وقوع زمین لغزش استخراج و سپس لایههای مربوطه تهیه گردید. در ادامه با تلفیق نقشه عوامل مؤثر بر لغزش با نقشه پراکنش زمین لغزشها، تأثیر هر یک از عوامل شیب، جهت شیب، سنگشناسی، بارش، کاربری اراضی، فاصله از گسل و آبراهه در محیط نرمافزار ArcGIS محاسبه گردید و نقشه پراکنش زمین لغزشهای رخداده حوضه تهیه شد. در این تحقیق مدل منطق فازی با اپراتورهای عملگر اجتماع فازی، عملگر اشتراک فازی، عملگر ضرب جبری فازی، عملگر جمع جبری فازی، عملگر گاما فازی بکار گرفته شد. بر اساس پهنهبندی صورت گرفته با استفاده از عملگر گاما فازی، به ترتیب 37/64، 45/7، 93/8، 49/12 و 76/6 درصد از مساحت منطقه در کلاسهای خطر خیلی کم، کم، متوسط، زیاد و خیلی زیاد قرار گرفته است. پرونده مقاله -
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11 - Localization Method for Wireless Sensor Networks Using Nero-Fuzzy
Ahmad Javan bakht Abolghasem AlibeikiA wireless sensor network (W SN) includes a series of nods , each of them containing some sensors which have a role in gathering data about the circuit in which they are distributed. Sensor networks enjoy variety of uses ; that is why they are attracted by many countrie چکیده کاملA wireless sensor network (W SN) includes a series of nods , each of them containing some sensors which have a role in gathering data about the circuit in which they are distributed. Sensor networks enjoy variety of uses ; that is why they are attracted by many countries . In a wireless sensor network , few nods have already known their position which are called anchor node ; other nods must calculate their position accordingly . In this essay “ received signal strength indicator ” and “ Nero-Fuzzy ” are used in order to calculate unspecified - position nods ’ coordinate . Each unspecified - position node must know the position of some nearing anchor nodes . The more the nodes are , the more precise the coordinate is . In this essay , unspecified node ’ s coordinate is estimated according to two or more anchor nodes using logic fuzzy . Since the range covered by sensor networks is broad , finding all anchor nodes is a time - consuming task and needs a lot of memory . Therefore , distance limit between anchor nodes and unspecified nodes is considered . The area around anchor nodes and unspecified nodes is divided reticulated , and then , the unspecified node ’ s coordinate is estimated according to logic fuzzy rules . The estimated average error rate for 120 nodes using this method equals to 2 % of radio range , which is minimal in comparison to APS algorithm . پرونده مقاله -
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12 - Multi-objective design of fuzzy logic controller in supply chain
Mahdi Ghane Mohammad Jafar Tarokh Jafar TarokhUnlike commonly used methods, in this paper, we have introduced a new approach for designing fuzzy controllers. In this approach, we have simultaneously optimized both objective functions of a supply chain over a two-dimensional space. Then, we have obtained a spectrum چکیده کاملUnlike commonly used methods, in this paper, we have introduced a new approach for designing fuzzy controllers. In this approach, we have simultaneously optimized both objective functions of a supply chain over a two-dimensional space. Then, we have obtained a spectrum of optimized points, each of which represents a set of optimal parameters which can be chosen by the manager according to the importance of objective functions. Our used supply chain model is a member of inventory and order-based production control system family, a generalization of the periodic review which is termed ‘Order-Up-To policy.’ An auto rule maker, based on non-dominated sorting genetic algorithm-II, has been applied to the experimental initial fuzzy rules. According to performance measurement, our results indicate the efficiency of the proposed approach. پرونده مقاله -
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13 - Development of a weighted leanness measurement method in modular construction companies
Saba Shams Bidhendi Steven Goh Andrew WandelThis paper outlines the development of an improved approach to the use of lean tools and techniques to improve the performance of manufacturing enterprises. Several research studies attempt to measure the overall leanness score of the manufacturing process; however, the چکیده کاملThis paper outlines the development of an improved approach to the use of lean tools and techniques to improve the performance of manufacturing enterprises. Several research studies attempt to measure the overall leanness score of the manufacturing process; however, they failed to consider the interdependent relationships between lean performance metrics and considered all performance measures to be equally important during analysis. This paper proposes the weighted leanness assessment methodology to further extend the most recent developed leanness assessment model. The developed methodology in this research provides an integrated leanness score of the production process which considers the interrelationships betweendifferent performance metrics due to competing for business and operational strategies. The fuzzy-based analytic network process approach is used to measure and allocate relative importance weightings to each performance metric. The result from the proposed methodology in this research provides a more accurate overall leanness score by prioritising different performance measures according to the manufacturer’s needs. A case study was conducted to illustrate the effectiveness and validity of the proposed model and methodologies. پرونده مقاله -
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14 - Efficacy of fuzzy MADM approach in Six Sigma analysis phase in automotive sector
Rajeev Rathi Dinesh Khanduja S. K. SharmaSix Sigma is a strategy for achieving process improvement and operational excellence within an organization. Decisions on critical parameter selection in analysis phase are always very crucial; it plays a primary role in successful execution of Six Sigma project and for چکیده کاملSix Sigma is a strategy for achieving process improvement and operational excellence within an organization. Decisions on critical parameter selection in analysis phase are always very crucial; it plays a primary role in successful execution of Six Sigma project and for productivity improvement in manufacturing environment and involves the imprecise, vague and uncertain information. Using a case study approach; the paper demonstrates a tactical approach for selection of critical factors of machine breakdown in center less grinding (CLG) section at an automotive industry using fuzzy logic based multi attribute decision making approach. In this context, we have considered six crucial attributes for selection of critical factors for breakdown. Mean time between failure is found to be the pivotal selection criterion in CLG section. Having calculated the weights pertinent to criteria through two methods (fuzzy VIKOR and fuzzy TOPSIS) critical factors for breakdown are prioritized. Our results are in strong agreement with the perceptions of production and maintenance department of the company. پرونده مقاله -
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15 - Coordination Between the Automatic Voltage Regulator and Output of the Power System Stabilizer to Increase the Stability Improvement
Majid Salesi-Mousaabadi Ghazanfar ShahgholianBy combining particle swarm optimization (PSO) and fuzzy logic controller (FLC), the ability of these methods to solve complex and nonlinear problems effectively improves power system stability. Setting the power system stabilizer parameters using the PSO method is pres چکیده کاملBy combining particle swarm optimization (PSO) and fuzzy logic controller (FLC), the ability of these methods to solve complex and nonlinear problems effectively improves power system stability. Setting the power system stabilizer parameters using the PSO method is presented in this paper. Fuzzy logic controller has been used for simultaneous weighting of the automatic voltage regulator and power system stabilizer output. First, the simulation has been carried out in a single-machine power system, where the optimal PSS parameters have been obtained using the PSO algorithm. Then, by simultaneously adjusting the voltage and damping by the fuzzy logic controller, the effectiveness of the proposed method is verified compared to the PSS based on the linear optimization controller. In the following, the simulation results of a multi-machine system are shown. The efficiency of the method has been shown in response to a variety of disorders پرونده مقاله -
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16 - An Improved MPPT Method of Wind Turbine Based on HCS Method by Using Fuzzy Logic System
Shahram Javadi Mohammad Hossein HazinIn this paper presents a Maximum Power Point Tracking (MPPT) technique based on the Hill Climbing Search (HCS) method and fuzzy logic system for Wind Turbines (WTs) including of Permanent Magnet Synchronous Generator (PMSG) as generator. In the conventional HCS method t چکیده کاملIn this paper presents a Maximum Power Point Tracking (MPPT) technique based on the Hill Climbing Search (HCS) method and fuzzy logic system for Wind Turbines (WTs) including of Permanent Magnet Synchronous Generator (PMSG) as generator. In the conventional HCS method the step size is constant, therefor both steady-state response and dynamic response of method cannot provide at the same time and in the fixed step size of HCS method. The propose method of this paper is improvement the performance HCS method, in order to reach this goal; the fuzzy logic system has been used. The fuzzy logic system based on operation condition determined the step size instantaneously, such as both steady-state response and dynamic response of method be proper at the same time, therefore, efficiency of the new method that used variable step size strategy, will be guaranteed, the results of simulation in environment MATLAB/Simulink software have been shown to be effectiveness of the proposed method. پرونده مقاله -
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17 - Power Stabilizer Performance Based On Fuzzy Controller Compared To PID Controller
Abbas SeifElectro-mechanical oscillations are produced in the machines of an interconnected power network, followed by a disturbance or due to high power transfer through weak tie lines. These oscillations should be damped as quickly as possible to ensure the reliable and stable چکیده کاملElectro-mechanical oscillations are produced in the machines of an interconnected power network, followed by a disturbance or due to high power transfer through weak tie lines. These oscillations should be damped as quickly as possible to ensure the reliable and stable operation of the network. To damp these oscillations different controllers, based on local or wide area signals, have been the subject of many papers. This paper presents the analysis of the PID of Conventional Power System Stabilizer (PSS) and Fuzzy Logic Controller. پرونده مقاله -
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18 - A New Highly Controllable and Accurate Algorithm for Defuzzifier Circuit Implementation
M Ranjbar F RazaghianDefuzzifier circuit is one of the most important parts of fuzzy logic controllers that determine the output accuracy. The Center Of Gravity method (COG) is one of the most accurate methods that so far been presented for defuzzification. In this paper, a simple algorithm چکیده کاملDefuzzifier circuit is one of the most important parts of fuzzy logic controllers that determine the output accuracy. The Center Of Gravity method (COG) is one of the most accurate methods that so far been presented for defuzzification. In this paper, a simple algorithm is presented to generate triangular output membership functions in the Mamdani method using the multiplier/divider circuit and mirror current CMOS technology. As well as the method simplicity, the method is highly accuracy and controllable in the height, slope of output membership functions, number of rules and number of input/output membership functions cause to use mixed voltages. This method covers each type of the input fuzzifier. The proposed Circuits in this paper are implemented by a standard 0.35um CMOS technology in Hspice software پرونده مقاله -
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19 - Design of Maximum Power Point Tracking in Solar Array Systems Using Fuzzy Controllers
Marjaneh Hashemi Shahram JavadiIn recent year's renewable energy sources have become a useful alternative for the power generation. The power of photovoltaic is nonlinear function of its voltage and current. It is necessary to maintain the operation point of photovoltaic in order to get the maximum p چکیده کاملIn recent year's renewable energy sources have become a useful alternative for the power generation. The power of photovoltaic is nonlinear function of its voltage and current. It is necessary to maintain the operation point of photovoltaic in order to get the maximum power point (MPP) in various solar intensity. Fuzzy logic controller has advantage in handling non-linear system. Maximum power point trackers are so important in photovoltaic systems to increase their efficiency. Many methods have been proposed to achieve the maximum power that the PV modules. This paper proposed an intelligent method for MPPT based on fuzzy logic controller. The system consists of a photovoltaic solar module connected to a DC-DC Boost converter and the fuzzy logic controller for controlling on/off time of MOSFET switch of a boost converter. The proposed MPPT controller for grid-connected photovoltaic system is tested using model designed by Matlab/Simulink program. Comparison of different performance parameters such as: tracking efficiency and response time of the system shows that the proposed method gives higher efficiency and better performance than the conventional perturbation and observation method. پرونده مقاله -
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20 - طراحی و تبین مدل نقد شوندگی سهام با توان رقابت بازار محصول براساس رویکرد تطبیقی مدل اقتصادسنجی و منطق فازی
حسن حیدری سلطان ابادی حسین پناهیانیکی از ریسک های مربوط به سهام شرکت، نقد شوندگی سهام است. سهام دارای نقد شوندگی بالا برای سهامداران و سرمایه گذاران جذاب بوده و تقاضای آن را افزایش می دهد.نقدشوندگی سهام به عنوان یکی از معیارهای موثر بر کارایی بازار، به خصوص به لحاظ اطلاعاتی است و به شکل گسترده در بررسی چکیده کاملیکی از ریسک های مربوط به سهام شرکت، نقد شوندگی سهام است. سهام دارای نقد شوندگی بالا برای سهامداران و سرمایه گذاران جذاب بوده و تقاضای آن را افزایش می دهد.نقدشوندگی سهام به عنوان یکی از معیارهای موثر بر کارایی بازار، به خصوص به لحاظ اطلاعاتی است و به شکل گسترده در بررسی عوامل موثر بر ارایه اطلاعات مفید به کار گرفته می شود. در این پژوهش به طراحی و تبین مدل نقدشوندگی سهام با توجه به مولفه رقابت محصول پرداخته شد. برای انتخاب نمونه، تمام شرکتهای پذیرفته شده در بورس اوراق بهادار تهران از سال 1386 تا سال 1397 بررسی شده است .ده متغیر اصلی تاثیرگذار بر نقدشوندگی وارد مدل پژوهش شدند و فرضیههای پژوهش با استفاده از مدل رگرسیونی مورد آزمون قرار گرفت، سپس از طریق آموزش و یادگیری در شبکه عصبی فازی که یک روش پژوهش تحلیلی- ریاضی است، مدل نقدشوندگی سهام ارائه گردید. پیشبینی حاصل از شبکه عصبی فازی بدلیل روش جستجوی فراگیر از دقت بالایی برخوردار و مدل نهایی با ضریب تعیین تعدیل شده 77 درصد تائید گردید. بر اساس نتایج بدست آمده، نقدشوندگی به پنج عامل تاثیرگذار شامل بازده سهام، اندازه شرکت، فرصت سرمایه گذاری، شاخص هرفیندال هیرشمن، شاخص لرنر بستگی دارد. پرونده مقاله