Control and Optimization
Hajar Alimorad
Abstract
While many real-world optimization problems typically involve multiple constraints, unconstrained problems hold practical and fundamental significance. They can arise directly in specific applications or as transformed versions of constrained optimization problems. Newton's method, ...
Read More
While many real-world optimization problems typically involve multiple constraints, unconstrained problems hold practical and fundamental significance. They can arise directly in specific applications or as transformed versions of constrained optimization problems. Newton's method, a notable numerical technique within the category of line search algorithms, is widely used for function optimization. The search direction and step length play crucial roles in this algorithm. This paper introduces an algorithm aimed at enhancing the step length within the Broyden quasi-Newton process. Additionally, numerical examples are provided to compare the effectiveness of this new method with another approach.
Rasool Hatamian Joghali
Abstract
In 2010, Alvarez et al. proposed an algorithm for morphological snakes that could detect objects whose edges consist of convex sets and polygonal edges. However, the algorithm may not detect the boundary well if the edges of an object contain a convex set or if there are several separated ...
Read More
In 2010, Alvarez et al. proposed an algorithm for morphological snakes that could detect objects whose edges consist of convex sets and polygonal edges. However, the algorithm may not detect the boundary well if the edges of an object contain a convex set or if there are several separated objects in an image. In this paper, we present two optimal sub-algorithms that are modifications to the Alvarez et al. algorithm. Our algorithms provide optimal edge detection for images and we present examples to demonstrate their effectiveness.
Mohammad Hamidi; Kamal Norouzi; Akbar Rezaei
Abstract
In this research, we use averages and relative measures of interval grey numbers to introduce grey vertices, grey edges, and grey graphs (graphs are based on interval grey numbers). To do so, we design a grey graph based on a graph (as the underlying graph). ...
Read More
In this research, we use averages and relative measures of interval grey numbers to introduce grey vertices, grey edges, and grey graphs (graphs are based on interval grey numbers). To do so, we design a grey graph based on a graph (as the underlying graph). Also, we find a relation between grey vertices and grey edges of a grey graph. The primary method used in this research is based on linear inequalities related to grey vertices and grey edges. We find some necessary and sufficient conditions on the grey vertex (as (non-)discrete grey vertices) connectivity of grey graphs based on interval grey numbers and linear inequality systems}.The paper includes implications for the development of(non-)weighted graphs, and the modeling of uncertainty problems by grey vertices, grey edges, and their relations in a grey model as a grey graph. As a weighted graph, a fuzzy graph is a vital graph that has some applications in the real world, but with changes in conditions, it loses its efficiency. On the other hand, the efficiency of a grey graph is stable under changes in the conditions. So, grey graphs cover the weaknesses of fuzzy graphs. The new conception of grey graphs based on grey numbers is introduced in this study. We propose an optimization method that can be applied for grey numbers in an extension of graphs, and apply it for gray numbers in the real world, especially for optimization problems and via gray graphs.
Aziz Zobeidi; Abdolhossein Neysi; Tahmoures Sohrabi
Abstract
The aim of this paper is to assess and optimize the interaction of stakeholders in the lean management process via a dynamic game theory approach within the National Southern Oilfields Company. The present research is applied in terms of the purpose, and qualitative in terms of the data. Also, in terms ...
Read More
The aim of this paper is to assess and optimize the interaction of stakeholders in the lean management process via a dynamic game theory approach within the National Southern Oilfields Company. The present research is applied in terms of the purpose, and qualitative in terms of the data. Also, in terms of its nature and the implementation method, it is based on foundational data. To form the framework of the optimal stakeholder interaction management strategy and measure its effects on lean management (including the dimensions of components and indicators, etc.), scientific and legal documents were studied, experts who utilized the Delphi technique were interviewed, relevant data were summarized and, focus groups and brainstorming were held based on the data foundation method. The findings revealed that the organization in charge of the game selected Stackelberg’s game instead of Nash's game, since compared to the latter, the former could produce more than twice when it came to total profit, production of suppliers and manufacturers, etc., thus showing a 100\% improvement compared to the cooperative games. In fact, in this study, the manufacturer under consideration preferred Stackelberg's game with the manufacturer acting as the leader and making decisions independent of the suppliers, gaining more profit and consequently more acceptance among people because of optimal production. In this model, three types of parameters played a key role in obtaining the outputs, the first of which was the cost of production. The rise in this parameter indicated the level of competition in profit and production. The second effective parameter was the coefficient of sensitivity to the level of demand for goods. An increase in this parameter caused a decrease in the profit and production of all members of the supply chain. Finally, the last effective parameter was the share of the base goods.
Control and Optimization
Zahra Abbasi; Nasser Akhoundi
Abstract
Product reviews in E-commerce websites such as restaurants, movies, E-commerce products, etc., are essential resources for consumers to make purchasing decisions on various items. In this paper, we model discovering groups with maximum descriptively ...
Read More
Product reviews in E-commerce websites such as restaurants, movies, E-commerce products, etc., are essential resources for consumers to make purchasing decisions on various items. In this paper, we model discovering groups with maximum descriptively from E-commerce website of the form $<i,u,s>$, where $i\in \mathcal{I}$ (the set of items or products), $u\in \mathcal{U}$ (the set of users) and $s$ is the integer rating that user $u$ has assigned to the item $i$. Labeled groups from user's attributes are found by solving an optimization problem. The performance of the approach is examined by some experiments on real data-sets.
Control and Optimization
Seyed Hamed Hashemi Mehne; Khodayar Javadi
Volume 2, Issue 2 , December 2017, , Pages 61-76
Abstract
A shape optimization problem of cooling fins for computer parts and integrated circuits is modeled and solved in this paper. The main purpose is to determine the shape of a two-dimensional pin fin, which leads to the maximum amount of removed heat. To do this, the shape optimization problem is defined ...
Read More
A shape optimization problem of cooling fins for computer parts and integrated circuits is modeled and solved in this paper. The main purpose is to determine the shape of a two-dimensional pin fin, which leads to the maximum amount of removed heat. To do this, the shape optimization problem is defined as maximizing the norm of the Nusselt number distribution at the boundary of the pin fin's connection profile. The governing differential equations are solved in solid and fluid phases separately. In order to formulate the optimization problem with finite dimensions, the shapes of the profiles are parameterized with cubic polynomials. Due to the lack of an explicit relation between the objective function and the geometric parameters, an approximate modeling method is used for the optimization process. The proposed method starts with three initial points. Then, the governing differential equations are solved for each of the profiles related to the initial points. The new step in this iterative process involves calculations based on a polynomial interpolation within the resulting Nusselt number norms. A numerical example is given to show the implementation and accuracy of the method.
Control and Optimization
Rohollah Alesheykh
Volume 1, Issue 2 , October 2016, , Pages 63-75
Abstract
The field of optimization and machine learning are increasingly interplayed and optimization in different problems leads to the use of machine learning approaches. Machine learning algorithms work in reasonable computational time for specific classes of problems and have important role in extracting ...
Read More
The field of optimization and machine learning are increasingly interplayed and optimization in different problems leads to the use of machine learning approaches. Machine learning algorithms work in reasonable computational time for specific classes of problems and have important role in extracting knowledge from large amount of data. In this paper, a methodology has been employed to optimize the precision of defect detection of concrete slabs depending on their qualitative evaluation. Based on this idea, some machine learning algorithms such as C4.5 decision tree, RIPPER rule learning method and Bayesian network have been studied to explore the defect of concrete and to supply a decision system to speed up the defect detection process. The results from the examinations show that the proposed RIPPER rule learning algorithm in combination with Fourier Transform feature extraction method could get a defect detection rate of 93% as compared to other machine learning algorithms.
