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جستجوی مقالات مرتبط با کلیدواژه « learning automata » در نشریات گروه « برق »

تکرار جستجوی کلیدواژه «learning automata» در نشریات گروه «فنی و مهندسی»
  • سید مهدی جامعی*
    امروزه تعداد برنامه های کاربردی که نیاز به زمان پاسخ دهی کمی دارند، روز به روز در حال افزایش است و بکارگیری محیط مه اخیرا مورد توجه زیادی قرار گرفته است. با توجه به پویایی استفاده از منابع در اکثر برنامه های اینترنت اشیا، نمی توان مکان ثابتی برای قرارگیری و اجرای سرویس ها در محیط مه در نظر گرفت و بنابراین باید سرویس ها در محیط مه به صورت پویا قرار داده شوند. مساله قرار دادن سرویس های مورد نیاز اینترنت اشیا در دستگاه های مه با محدودیت منابع، به عنوان یک مساله NP-hard شناخته می شود. در این مقاله، روشی پویا مبتنی بر الگوریتم ژنتیک چندهدفه با رتبه بندی نامغلوب جهت حل این مساله ارائه می گردد. در روش پیشنهادی، از اتوماتای یادگیر، جهت بهبود رفتار ژنتیکی و تنظیم پویای نرخ جهش و تقاطع استفاده می شود. روش پیشنهادی با استفاده از نرم افزار iFogsim شبیه سازی شده و نتایج شبیه سازی نشان می دهد روش پیشنهادی با در نظر گرفتن همزمان سه معیار تاخیر سرویس، هزینه و انرژی مصرفی، کارایی بهتری را نسبت به الگوریتم های مورد مقایسه دارد. از نظر هزینه، در مقایسه با دو روش CSA و LRFC به ترتیب 11 و 21 درصد کاهش داشته است. همچنین روش پیشنهادی از نظر میانگین تاخیر سرویس دهی نسبت به دو روش CSA و HAFA به ترتیب 7 و 15 درصد کاهش داشته است. از نظر انرژی مصرفی نیز روش پیشنهادی نسبت به روش های دیگر بهبود حداقل 8 درصدی را نشان می دهد.
    کلید واژگان: اینترنت اشیا, محاسبات مه, محاسبات ابری, تامین پویای سرویس, الگوریتم ژنتیک, ماشین یادگیر}
    Seyed Mahdi Jameii *
    Nowadays, the number of applications that require a short response time is increasing, and utilizing fog environment has recently received a lot of attention. Due to the dynamics of the resource usage pattern in most Internet of Things applications, a fixed location cannot be considered for the placement and execution of services in the fog environment, and therefore the services must be dynamically placed in the fog environment. The problem of placing required Internet of Things services in cloud devices with limited resources is known as an NP-hard problem. In this article, a dynamic method based on multi-objective genetic algorithm with non-dominated ranking is presented to solve this problem. In the proposed method, learning automata are used to improve genetic behavior and dynamically adjust mutation and crossover rates. The proposed method is simulated using iFogsim and the simulation results show that the proposed method has a better efficiency than the compared algorithms by simultaneously considering the three criteria of service delay, cost and energy consumption. In terms of cost, compared to the two CSA and LRFC methods, it has decreased by 11% and 21%, respectively. Also, in terms of the average service delay, compared to the CSA and HAFA methods, the proposed method has decreased by 7% and 15 %, respectively. In terms of energy consumption, the proposed method shows an improvement of at least 8% compared to other methods.
    Keywords: Iot, Fog Computing, Cloud Computing, Dynamic Service Provisioning, Genetic Algorithm, Learning Automata}
  • محمدرضا ملاخلیلی میبدی، معصومه زجاجی

    در این مقاله ابتدا نوعی از بهینه‌سازی جایگشت معرفی شده است. در این نوع بهینه‌سازی فرض گردیده که تابع هزینه، دارای یک تابع توزیع احتمال ناشناخته است. این فرض باعث می‌شود که پیچیدگی حل مسیله یافتن جایگشت بهینه که به دلیل بزرگی ذاتی فضای جواب‌ها پیچیده است، تشدید شود. یک الگوریتم مبتنی بر آتاماتای یادگیر توزیع‌شده برای حل مسیله از طریق انجام توامان جستجو در فضای جواب‌های جایگشت و نمونه‌گیری از مقادیر تصادفی ارایه می‌دهیم. ضمن بررسی ریاضی رفتار الگوریتم جدید پیشنهادی، نشان می‌دهیم که با انتخاب مقادیر مناسب پارامترهای الگوریتم یادگیر، این روش جدید می‌تواند جواب بهینه را با احتمالی به اندازه دلخواه نزدیک به 100% و از طریق هدفمندکردن جستجو به کمک آتاماتای یادگیر توزیع‌شده پیدا کند. نتیجه اتخاذ این سیاست، کاهش تعداد نمونه‌گیری‌ها در روش جدید در مقایسه با روش‌های مبتنی بر نمونه‌گیری استاندارد است. در ادامه، مسیله یافتن درخت پوشای کمینه در گراف تصادفی به عنوان یک مسیله بهینه‌سازی جایگشت تصادفی بررسی گردیده و راه حل ارایه‌شده مبتنی بر آتاماتای یادگیر برای حل آن به کار گرفته شده است.

    کلید واژگان: آتاماتای یادگیر, آتاماتای یادگیر توزیع شده, گراف تصادفی, درخت پوشای کمینه تصادفی}
    mohammadreza mollakhalili meybodi, masoumeh zojaji

    In the present research, a type of permutation optimization was introduced. It is assumed that the cost function has an unknown probability distribution function. Since the solution space is inherently large, solving the problem of finding the optimal permutation is complex and this assumption increases the complexity. In the present study, an algorithm based on distributed learning automata was presented to solve the problem by searching in the permutation answer space and sampling random values. In the present research, in addition to the mathematical analysis of the behavior of the proposed new algorithm, it was shown that by choosing the appropriate values of the parameters of the learning algorithm, this new method can find the optimal solution with a probability close to 100% and by targeting the search using the distributed learning algorithms. The result of adopting this policy is to decrease the number of samplings in the new method compared to methods based on standard sampling. In the following, the problem of finding the minimum spanning tree in the stochastic graph was evaluated as a random permutation optimization problem and the proposed solution based on learning automata was used to solve it.

    Keywords: Learning automata, distributed learning automata, stochastic graph, stochastic minimum spanning tree}
  • Mohammad Irandoost *, Mona Salehi
    Since Software-Defined Network is a logically centralized technology, the importance of scalability of the control plane has increased with increasing network scales. Therefore, the use of multiple controllers was proposed instead of a centralized controller. Although multiple controllers have solved scalability in software-based networks, they faced load imbalance on controllers due to the static assignment between the controllers and the switches. As a result, switch migration is proposed as an efficient approach to solving static allocation between the controller and switch. Switch migration allows a dynamic connection between controllers and switches, but which controller or switch is suitable for migration has become a vital problem issue in itself. A learning automaton with a variable structure is proposed to select the target controller in the proposed method. All selection and environment reaction cases are evaluated with learning automata, and choose the best controller for migration costs. The proposed method has been compared with state-of-the-art algorithms. The results showed that the proposed approach could reduce the delays of sending packets in the network by balancing the controllers with the optimal selection of target controllers for switch migration.
    Keywords: Software-Defined Networks, Load balancing, Switch Migration, Learning Automata}
  • Maryam Hajiee, Mehdi Fartash, Nafiseh Osati Eraghi

    The use of wireless sensor networks is becoming more and more important due to the COVID - 19 pandemic and the living conditions of human beings today. The three main goals in designing this type of network are to reduce energy consumption, choose the shortest route and choose a reliable route for data transmission. In this paper, these th ree goals are considered in routing. Due to the fact that this type of network is exposed to many attacks, identifying malicious nodes and removing them creates security in this type of network. This paper presents an energy - aware and trusted - based routing method using learning automata and an evaluation function. Learning automata identifies trusted nodes (to send data) and malicious nodes using the corresponding evaluation function. The evaluation function considers the residual energy, the node's trust a nd the number of hops to the sink parameters. Thus, the data reaches its destination in a safe and reliable way. The evaluation results of the proposed method show an improvement in the performance of this method compared to other relevant methods.

    Keywords: Wireless Sensor Network, Trust, Learning Automata, Security}
  • Sara Taghipour, Javad Akbari Torkestani *, Sara Nazari
    Collaborative Filtering (CF) is one of the principal techniques applied in Recommender Systems, which uses ratings from similar users to predict interest items to a particular user. The scalability issue is a widespread problem of CF. The clustering technique is a successful approach to address the scalability issue in CF. However, some classic clustering methods cannot find appropriate clusters, which leads to low prediction accuracy. This paper suggests a new clustering algorithm based on the Learning Automata (LA) framework to group users for the CF technique. In this algorithm, a learning automaton is assigned to each user to detect the cluster membership of that user. Learning automatons improve their selection based on the reinforcement signal is received from intra-cluster distances and inter-cluster distances in previous iterations.Experimental results on standard and real datasets show that the proposed algorithm outperforms other compared methods in various evaluation metrics. This approach enhances the prediction accuracy and effectively deals with the scalability problem.
    Keywords: collaborative filtering, Clustering, Learning Automata, Recommender Systems}
  • Shoorangiz Shams Shamsabad Farahani

    Wireless Sensor Networks (WSNs) are a special class of wireless ad-hoc networks where their performance is affected by different factors.Congestion is of paramount importance in WSNs. It badly affects channel quality, loss rate, link utilization, throughput, network life time, traffic flow, the number of retransmissions, energy, and delay. In this paper, congestion control schemes are classified as classic or softcomputing-based schemes. The soft computing-based congestion control schemes are classified as fuzzy logic-based, game theory-based, swarm intelligence-based, learning automata-based, and neural network-based congestion control schemes. Thereafter, a comprehensive review of different soft computing-based congestion control schemes in wireless sensor networks is presented. Furthermore, these schemes are compared using different performance metrics. Finally, specific directives are used to design and develop novel soft computing-based congestion control schemes in wireless sensor networks

    Keywords: Congestion Control, Fuzzy Logic, Game Theory, Learning Automata, Neural Network, Soft Computing, Swarm Intelligence, Wireless Sensor Networks (WSNs)}
  • Z. Anari, A. Hatamlou *, B. Anari, M. Masdari

    The Transactions in web data often consist of quantitative data, suggesting that fuzzy set theory can be used to represent such data. The time spent by users on each web page is one type of web data, was regarded as a trapezoidal membership function (TMF) and can be used to evaluate user browsing behavior. The quality of mining fuzzy association rules depends on membership functions and since the membership functions of each web page are different from those of other web pages, so automatic finding the number and position of TMF is significant. In this paper, a different reinforcement-based optimization approach called LA-OMF was proposed to find both the number and positions of TMFs for fuzzy association rules. In the proposed algorithm, the centers and spreads of TMFs were considered as parameters of the search space, and a new representation using learning automata (LA) was proposed to optimize these parameters. The performance of the proposed approach was evaluated and the results were compared with the results of other algorithms on a real dataset. Experiments on datasets with different sizes confirmed that the proposed LA-OMF improved the efficiency of mining fuzzy association rules by extracting optimized membership functions.

    Keywords: web usage mining, learning automata, fuzzy set, membership function, fuzzy association rule}
  • Neda Zekrizadeh, Ahmad Khademzadeh*, Mehdi Hosseinzadeh

    Task scheduling is one of the main and important challenges in the cloud environment. The dynamic nature and changing conditions of the cloud generally leads to problems for the task scheduling. Hence resource management and scheduling are among the important cases to improve throughput of cloud computing. This paper presents an online, a non-preemptive scheduling solution using two learning automata for the task scheduling problem on virtual machines in the cloud environment that is called LABTS. This algorithm consists three phases: in the first one, the priority of tasks sent by a learning automaton is predicted. In the second phase, the existing virtual machines are clustered according to the predictions in the previous phase. Finally, using another learning automaton, tasks are assigned to the virtual machines in the third phase. The simulation results show that the proposed algorithm in the cloud environment reduces the value of two parameters makespan and degree of imbalance.

    Keywords: cloud computing, learning automata, task scheduling, priorities of tasks}
  • مهدی رضاپور میرصالح *، محمدرضا میبدی
    الگوریتم ممتیک یکی از انواع الگوریتم های تکاملی است که با استفاده از جستجوی عمومی و جستجوی محلی فضای حل مساله را به صورت بهینه جستجو می نماید. تعادل بین جستجوی عمومی و محلی، همواره یکی از مسایل مهم در این دسته از الگوریتم ها است. در این مقاله یک مدل جدید ممتیکی با نام 2GALA ارائه شده است. این مدل از ترکیب الگوریتم ژنتیک و اتوماتای مهاجرت اشیا که نوع خاصی از اتوماتای یادگیر ساختار ثابت می باشد، تشکیل شده است. در مدل ارائه شده جستجوی عمومی توسط الگوریتم ژنتیک و یادگیری محلی به وسیله اتوماتای یادگیر انجام می شود. در این مدل جهت افزایش سرعت همگرایی و فرار از همگرایی زودرس، به طور هم زمان از دو مدل یادگیری لامارکی و بالدوینی استفاده شده است. در این مدل تکاملی، جهت استفاده توام از اثرات مثبت تکامل و یادگیری محلی، کروموزم ها به وسیله اتوماتای مهاجرت اشیا بازنمایی شده اند. جهت نمایش برتری مدل ارائه شده نسبت به سایر روش های موجود، از این مدل برای حل مساله تناظر گراف استفاده گردیده است.
    کلید واژگان: الگوریتم ممتیک, مم, جستجوی محلی, جستجوی عمومی, اتوماتای یادگیر, اتوماتای مهاجرت اشیا}
    M. Rezapoor Mirsaleh *, M. R. Meybodi
    Memetic algorithm (MA) is a kind of evolutionary algorithms (EAs) that searches the problem solving space using local search and global search. The balance between global search and local search is one of the key issues in this algorithm. In this paper a new model is proposed, called GALA2. This model is combined of genetic algorithm (GA) and object migration automata (OMA), which is a kind of fixed-structure learning automaton. In the proposed model, global search is performed by genetic algorithm and local learning is performed by learning automata. In this model, the Lamarckian and Baldwinian learning models have been used to increase the convergence rate and avoidance of premature convergence, simultaneously. In this evolutionary model, chromosomes are represented by object migration automata for the purpose of using positive effects of evolution and local learning. In order to show the superiority of the proposed model, GALA2 is used to solve the graph isomorphism problem.
    Keywords: Memetic algorithm, Meme, local search, global search, learning automata, object migration automata}
  • Hajar Hajary, Ali Ahmadi *, Maryam Khani
    Determining the best way of learning and acquiring knowledge, especially in intelligent tutoring systems has drawn researcher's attention during past years. Studies conducted on E-learning systems and strategies proposed to improve the quality of these systems, indicate that the main learning resources for students in an educational environment are provided by two crucial factors. The first is the teacher who can basically influence students’ success through demonstrating her ability and skills, and the second is interaction among students. In this article, a new modeling approach is presented for improving learning/teaching models as well as interaction among learners, from which the most benefit can be derived by learners. The proposed model uses the learning automata for modeling the teacher and her behavior in such a way that she can also learn and teach better at the same time, thus improves her teaching skills. The model also uses cellular learning automata in order to model behavior of the learners as well as interactions between the learners for knowledge acquisition. The results indicate that in addition to teacher’s skills, the interaction/communication among learners can significantly improve the quality and speed of learning as compared with previous methods.
    Keywords: tutorial like system, interactions, learning automata, cellular learning automata}
  • Zahra Reisi, Omid Bushehrian*, Farahnaz Rezaeian Zadeh
    Due to the elastic nature of the cloud environments, migration of the legacy software systems to the cloud has become a very attractive solution for service providers. To provide Software-as-a-Service (SaaS), an application provider has to migrate his software to the cloud infrastructure. The most challenging issue in the migration process is minimizing the cloud infrastructure (VM’s) costs while preserving the quality requirements of the service consumers. In this paper a self-adaptive method for migrated applications to the cloud is proposed in which an intelligent auto-scaling component continuously monitors the incoming application workloads and performs vertical or horizontal scaling. Since reacting to the transient workload changes always results in useless sequences of “acquire-release” actions of cloud resources and imposes unwanted overhead costs on the service provider, the auto-scaling component recognizes the transient workloads using a Learning Automata and only reacts to the stable ones. The OpenStack platform is used for evaluating the applicability of proposed method in real cloud environments. The experimental results demonstrate the ability of the proposed method in recognizing the transient workloads and consequently reducing the overall costs of the service provider.
    Keywords: Migration to Cloud, Auto, Scaling, Learning Automata, Transient Workload}
  • Hajar Hajary*, Ali Ahmadi
    Determining the best way of learning and acquiring knowledge, especially in intelligent tutoring systems have drawn researcher's attention during past years. With regard to studies conducted on E-learning systems and strategies proposed to improve the quality of these systems, it can be said that the interactions play a vital role in the educational systems. Therefore, the learners are not only affected by the teacher in a learning environment but also significantly learn important materials through the interaction with other learners. In this article, a new modeling approach is presented for improving learning/teaching models as well as interaction among learners, from which the most benefit can be derived by learners. The proposed model uses cellular learning automata in order to model behavior of the learners as well as interactions between the learners for knowledge acquisition. This algorithm also deals with the process of teaching as well as education of the learners. The results indicate that relationship between the learners can improve their knowledge and also increase their learning speed compared to previous methods.
    Keywords: learning automata, cellular learning automata, interactive learning, tutorial-like system}
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