به جمع مشترکان مگیران بپیوندید!

تنها با پرداخت 70 هزارتومان حق اشتراک سالانه به متن مقالات دسترسی داشته باشید و 100 مقاله را بدون هزینه دیگری دریافت کنید.

برای پرداخت حق اشتراک اگر عضو هستید وارد شوید در غیر این صورت حساب کاربری جدید ایجاد کنید

عضویت
جستجوی مقالات مرتبط با کلیدواژه

non-linear programming

در نشریات گروه فنی و مهندسی
تکرار جستجوی کلیدواژه non-linear programming در مقالات مجلات علمی
  • Maryam Arshi, Abdollah Hadi-Vencheh, Adel Aazami*, Ali Jamshidi

    Linguistic variables (LVs) provide a reliable expression of cognitive information. By inheriting the advantages of LVs, we can express uncertain and incomplete cognitive information in multiple attribute decision-making (MADM), and they do so better than existing methods.  In the decision-making process, we can consider decision experts’ (DEs’) bounded rationality, such as cognition toward loss caused by the DEs’ cognitive limitations during the decision process. Therefore, it is necessary to propose a novel cognitive decision approach to handle MADM problems in which the cognitive information is expressed by LVs. In this paper, we employ LVs to represent uncertain and hesitant cognitive information. Then, we propose a mathematical programming approach to solve the MADM problems where attributes or cognitive preferences are not independent.  Moreover, the validity and superiority of the presented approach are verified by dealing with a practical problem.

    Keywords: Multiple Attribute Group Decision Making (MAGDM), Interval-Valued Neutrosophic Number (IVNN), Non-Linear Programming, Variable Transformation, Aggregation Operators
  • Mahya Hemmati, Seyed Mohammad Taghi Fatemi Ghomi*, Mohsen Sheikh Sajadieh

    This paper studies a name-your-own-price (NYOP) mechanism in which the retailer allows buyers to participate in the pricing process by submitting bids. Buyers can place both joint and individual bids to purchase products either as a bundle or individually. The retailer utilizes NYOP and posted-price channels simultaneously. The focus of this paper is to assess the impact of adding the postedprice channel and bundling option on buyer behavior and retailer profit. The paper develops a two-stage model where the first stage involves the buyer’s decision on participating in NYOP. Moreover, buyers can choose between bidding for a bundle or a single item. Decisions in the second stage depend on the outcome of the first stage. Four distinct purchasing scenarios are formulated to outline the potential ways that buyers can use to purchase products. Furthermore, the buyers’ learning effect on their bidding strategy is considered. A dynamic programming approach with backward induction is employed to solve the problem. Moreover, the concavity analysis is used to obtain the solution of each nonlinear subproblem. Then, a solution algorithm based on mathematical analysis is proposed. Results reveal that the frictional costs of the first period have a greater impact on the buyer utility than those of the second period. Moreover, applying the NYOP alongside the posted-price can enhance the retailer’s profit. In particular, the retailer can use the NYOP and bundling mechanisms as encouraging tools to attract buyers and increase his profit. Thus, NYOP is a very effective instrument for market penetration.

    Keywords: Participative pricing, Name-your-own-price, Bundling, Dynamicprogramming, Convex optimization, Non-linear programming
  • روح الله وحدانی، حسین خالقی، محسن فلاح جوشقانی

    در این مقاله، از کدهای فضا زمان برای رادار MIMO برای رسیدن به وضوح بالا در برد و سرعت هدف استفاده شده است. تابع ابهام دوبعدی به عنوان یک ابزار برای مقایسه عملکرد رادار در زمینه قدرت تفکیک شناخته می شود. یک کد فضا زمان می تواند بر اساس کمینه سازی فاصله بین پارامترهای واقعی هدف در برد، سرعت و زاویه طراحی شود. بدین منظور می توان با تحلیل تابع ابهام و باریک سازی آن در حد امکان به قدرت تفکیک بالا دست یافت. در این مقاله، تابع ابهام با دو متغیر عدم انطباق دامنه و سرعت در نظر گرفته شده و یک معیار جدید برای دستیابی به عملکرد با وضوح بالا در این زمینه پیشنهاد گردیده است. در این مورد با استفاده از بهینه سازی توابع هزینه پیشنهادی، کد فضا زمان مطلوب استخراج می شود. طرح پیشنهادی را می توان به رادار آرایه فازی MIMO نیز تعمیم داد. همچنین نتایج شبیه سازی نشان می دهد که طرح پیشنهادی ما دارای تابع ابهام بسیار باریک در اطراف مبدا است در حالی که عملکرد بسیار نزدیک به حالت بهینه در زمینه احتمال شناسایی هدف را نیز دارا می باشد.

    کلید واژگان: کد فضا زمان، رادار آرایه فازی MIMO، قدرت تفکیک، تابع ابهام، برنامه ریزی غیر خطی
    Roholah Vahdani, Hossein Khaleghi *, Mohsen Fallah Joshaghani

    In this paper, space-time codes for MIMO radar are used to achieve high resolution at target range and speed. The two-dimensional ambiguity function is known as a tool to compare radar performance in terms of resolution. A space-time code can be designed based on minimizing the distance between the actual target parameters in range, speed and angle. For this purpose, high resolution can be achieved by analyzing the ambiguity function and narrowing it down as much as possible. In this paper, the ambiguity function with two variables of amplitude and speed mismatch is considered and a new criterion to achieve high resolution performance in this field is proposed. In this case, by optimizing the proposed cost functions, the optimal space-time code is extracted. The proposed design can also be extended to phased-MIMO radar. The simulation results also show that our proposed scheme has a very narrow ambiguity function around the origin, while it has a performance very close to the optimal state in terms of target identification probability.

    Keywords: Space-time code, phased-MIMO radar, resolution, ambiguity function, non-linear programming
  • Mohammad Movafaghpour *
    The Analytic Hierarchy Process (AHP) which was developed by Saaty is a decision analysis tool. It has been applied to many different decision fields. Acquiring Pairwise Comparison Matrices (PCM) is the main step in AHP and also is frequently used in other multi-criteria decision-making methods. In a real problem when the number of alternatives/criteria to be compared is increased, the number of Pairwise Comparisons (PC) often becomes overwhelming. Since the Decision Maker’s (DM) performance in representing the relative preferences tends to deteriorate in such cases, it is preferred to gather fewer data from each individual DM in the form of pairwise comparisons. Missing values in Pairwise Comparison Matrices (PCM) in AHP is a spreading problem in areas dealing with great or dynamic data. The aim of this paper is to present an efficient mathematical programming model for estimating preference vector of pairwise comparison matrices with missing entries.
    Keywords: Incomplete Pairwise Comparisons, Analytic Hierarchy Process, Non-linear Programming, Optimum Solution, Dynamic Data
  • M. Movafaghpour *
    The purpose of this study is to provide a proper method for evaluating performance of teachers, which leads to authorities awareness about the quality and quantity of activities that are acceptable to the organization; also creating the grounds for empowering human resources, reduction of dissatisfaction, and complaints. This can result in eliminating discrimination or unfair judgments and therefore reduction of tensions, and conflicts between managers and employees. The Analytic Hierarchy Process (AHP) which was developed by Saaty is a decision analysis tool. It has been applied to many different decision fields. In this paper, we use AHP as a performance assessment tool to inquire diverse assessments in the organization about the performance of each employee. Since the number of the items to be compared in AHP is increased, the number of pairwise comparisons that each assessor answer, are increased drastically. So, we develop a method called EVMP to elicit the preference vector of pairwise comparison matrices with missing entries. The newly developed method is tested in a school; the generated results have been proved by experts.
    Keywords: Performance Assessment, Analytic Hierarchy Process, Non-linear Programming, Missing Judgments
  • Seyed Mohammad Binesh *, S. Rasekh
    An adaptive mesh-free approach is developed to compute the lower bounds of limit loads in plane strain soil mechanics problems. There is no pre-defined connectivity between nodes in the mesh-free techniques and this property facilitates the implementation of h-adaptivity. Nodes may be added, moved or discarded without complex changes in the data structures involved. In this regard, the Shepard mesh-free method is used in conjunction with the nodal stress rate smoothing technique and the lower bound limit analysis theory to establish a non-linear optimization problem. This problem is solved by second order cone programming technique and the result is a stress field that satisfied the lower bound requirements in non-rigorous manner. The lack of rigorousness arises from relaxation during nodal stress rate smoothing process. An error estimator is introduced by the application of Taylor series expansion and, by controlling the local error via a user-defined tolerance, the adaptive refinement strategy has been established. To demonstrate the effectiveness of proposed method, the procedure is applied to the examples of purely cohesive and cohesive-frictional soils.
    Keywords: adaptive, mesh-free, Lower bound, non-linear programming, plane strain
  • سودابه قهرمانی*، افشین لشکرآرا

    اساسا مسیله تامین توان راکتیو بهینه در شبکه قدرت توسط تپ چنجر تحت بار، ظرفیت بهینه ی خازن، ولتاژ ژنراتورهای تحت بار ثابت و یکنواخت کنترل می شود. در این مقاله یک روش بهینه سازی چند هدفه برای مسیله پخش بار راکتیو بهینه با استفاده از روش محدودیت ε برای فرمول بندی برنامه ریزی ریاضی وار چند هدفه ارایه شده است. توابع هدف مدل پیشنهادی شامل بهینه کردن هزینه سوخت ژنراتورها، تلفات توان اکتیو و بارپذیری سیستم می باشد. به خاطر اینکه متغیرهای کنترل، متغیرهای گسسته می باشند (توان راکتیو خروجی بانک های خازنی و نسبت تپ ترانسفورماتورها)، پخش بار راکتیو بهینه به عنوان یک مسیله برنامه ریزی غیرخطی آمیخته به عدد صحیح فرمول بندی شده است. تنظیمات بهینه تپ ترانسفورماتور ها مستقیما در معادلات ماتریس ادمیتانس شبکه تعیین شده است، زیرا که ماتریس ادمیتانس در پیکره بهینه سازی به عنوان قیود تساوی اضافی ایجاد می شود. برای نشان دادن کارایی روش پیشنهادی، نتایج با موارد تک هدفه، دو هدفه و سه هدفه مقایسه شده اند. الگوریتم پیشنهادی در مدلسازی و با استفاده حل کننده ی برای تولید جواب های بهینه پارتو حل شده است. در این تحقیق یک ابزار تصمیم گیری فازی جهت انتخاب بهترین جواب مصالحه ای از بین جواب های پارتو طراحی گردیده است. الگوریتم پیشنهادی روی سیستم آزمون 14 شینه ی اجرا شده است. نتایج شبیه سازی نشان می دهد که الگوریتم پیشنهادی بطور موثری قادر به کنترل پخش بار راکتیو و بهینه نمودن توابع هدف مورد نظر می باشد.

    کلید واژگان: پخش بار راکتیو بهینه، کمینه سازی تلفات، برنامه ریزی غیر خطی آمیخته به عدد صحیح، الگوریتم OA، ER، AP
    S. Ghahremani*, A. Lashkarara

    The measure of Reactive power optimization of main power network mainly considers on-load tap changer, the optimal capacity of the capacitor, the voltage of generator under the steady load. In This paper, a multi-objective optimization methodology to the Optimal Reactive Power Flow (ORPF) problem is proposed in which the e-constrained approach is implemented for the Multi-objective Mathematical Programming (MMP) formulation. The objective functions of the proposed model include optimize the total fuel cost, the active power losses, and the system load ability. Since the control variables include discrete variables (var sources and transformer tap ratios), the ORPF is inherently a mixed-integer nonlinear programming (MINLP) problem. The optimum tap settings of transformers are directly determined in terms of the admittance matrix of the network since the admittance matrix is constructed in the optimization framework as additional equality constraints. To show the effectiveness of proposed method the results are compared with single-objective, two-objectives and three-objectives. Finally, the method has been implemented in GAMS and solved using DICOPT solver to obtain optimal solutions. In this research, for selection of the best compromising answer among the Pareto optimal solutions has been designed a fuzzy decision-maker tool. The algorithm is tested on standard IEEE 14- bus test system. Simulation results show that the proposed algorithm is able to control reactive power flow effectively and optimize the selected objective functions.

    Keywords: Non-Linear Programming, OA, ER, AP algorithm, Reactive power flow
نکته
  • نتایج بر اساس تاریخ انتشار مرتب شده‌اند.
  • کلیدواژه مورد نظر شما تنها در فیلد کلیدواژگان مقالات جستجو شده‌است. به منظور حذف نتایج غیر مرتبط، جستجو تنها در مقالات مجلاتی انجام شده که با مجله ماخذ هم موضوع هستند.
  • در صورتی که می‌خواهید جستجو را در همه موضوعات و با شرایط دیگر تکرار کنید به صفحه جستجوی پیشرفته مجلات مراجعه کنید.
درخواست پشتیبانی - گزارش اشکال