Yazar "İnal, Ali Fırat" seçeneğine göre listele

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    A Multi-Agent Reinforcement Learning Approach to the Dynamic Job Shop Scheduling Problem
    (Mdpi, 2023) İnal, Ali Fırat; Sel, Çağrı; Aktepe, Adnan; Türker, Ahmet Kürşad; Ersöz, Süleyman
    In a production environment, scheduling decides job and machine allocations and the operation sequence. In a job shop production system, the wide variety of jobs, complex routes, and real-life events becomes challenging for scheduling activities. New, unexpected events disrupt the production schedule and require dynamic scheduling updates to the production schedule on an event-based basis. To solve the dynamic scheduling problem, we propose a multi-agent system with reinforcement learning aimed at the minimization of tardiness and flow time to improve the dynamic scheduling techniques. The performance of the proposed multi-agent system is compared with the first-in-first-out, shortest processing time, and earliest due date dispatching rules in terms of the minimization of tardy jobs, mean tardiness, maximum tardiness, mean earliness, maximum earliness, mean flow time, maximum flow time, work in process, and makespan. Five scenarios are generated with different arrival intervals of the jobs to the job shop production system. The results of the experiments, performed for the 3 x 3, 5 x 5, and 10 x 10 problem sizes, show that our multi-agent system overperforms compared to the dispatching rules as the workload of the job shop increases. Under a heavy workload, the proposed multi-agent system gives the best results for five performance criteria, which are the proportion of tardy jobs, mean tardiness, maximum tardiness, mean flow time, and maximum flow time.
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    A Systematic Literature Review of the Predictive Maintenance from Transportation Systems Aspect
    (Mdpi, 2022) Ersöz, Olcay Özge; İnal, Ali Fırat; Aktepe, Adnan; Türker, Ahmet Kürşad; Ersöz, Süleyman
    With the rapid progress of network technologies and sensors, monitoring the sensor data such as pressure, temperature, current, vibration and other electrical, mechanical and chemical variables has become much more significant. With the arrival of Big Data and artificial intelligence (AI), sophisticated solutions can be developed to prevent failures and predict the equipment's remaining useful life (RUL). These techniques allow for taking maintenance actions with haste and precision. Accordingly, this study provides a systematic literature review (SLR) of the predictive maintenance (PdM) techniques in transportation systems. The main focus of this study is the literature covering PdM in the motor vehicles' industry in the last 5 years. A total of 52 studies were included in the SLR and examined in detail within the scope of our research questions. We provided a summary on statistical, stochastic and AI approaches for PdM applications and their goals, methods, findings, challenges and opportunities. In addition, this study encourages future research by indicating the areas that have not yet been studied in the PdM literature.
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    Atölye tipi üretimde dinamik çizelgeleme problemi için tezgâh yükleme kurallarının kıyaslanması
    (Kırıkkale Üniversitesi, 2018) İnal, Ali Fırat; Türker, Ahmet Kürşad
    Çalışmanın ilk aşamasında; literatürde en sık kullanılmış olan 30 adet tezgâh yükleme kuralı ve bu kuralları kıyaslayabilmek için 9 adet performans ölçütü tespit edilmiştir. ARENA® paket programıyla dinamik bir atölye ortamının simülasyon modeli hazırlanarak, tespit edilen 30 kuralın performansları bulunmuş ve kıyaslanmıştır. Kıyaslamalar neticesinde, gecikmeleri azaltan kurallar belirlenmiş ve bu kurallar arasından SPRO (slack per remaining operations) kuralının bir adım öne çıktığı görülmüştür. Çalışmanın ikinci aşamasında; SPRO kuralının çalışma mantığı, EDD (earliest due date) kuralı ile birleştirilmiştir ve bu kurala kısaca EDDPRO adı konulmuştur. EDDPRO kuralı, daha önce belirlenmiş olan 30 kural ile aynı simülasyon modelinde denenmiş ve gecikmeler için olumlu sonuçlar verdiği sayısal veriler ile kanıtlanmıştır.
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    Evaluation of Profession Predictions for Today and the Future with Machine Learning Methods: Emperical Evidence From Turkey
    (Gazi Univ, 2023) Karaahmetoglu, Ebru; Ersöz, Süleyman; Türker, Ahmet Kürşat; Ateş, Volkan; İnal, Ali Fırat
    For the purpose of evaluating present and future trends of professions within the labor market, text mining approach could be an alternative to more traditional approaches such as employer surveys. Specifically, machine learning algorithms are used for making accurate predictions about the future directions of the professions which consequently will influence professional development of labour force. The aim of this study is to investigate the professions of the future and current in Turkey by the application of supervised learning algorithms and clustering methods to various Turkish data including documents belonging to Turkey's institutions. In this study, the popular professions were predicted with an accuracy rate between congruent to 0.81 and congruent to 0.93 thorough various machine learning algorithms. It was discovered that methodologically perceptron and stochastic gradient descent algorithms demonstrated superiority over other algorithms thanks to their intelligence functions. Furthermore, the analysis of current professions in Turkey revealed that the class of Professional occupations, Managers and Technicians and assistant professional members were popular, and according to the analysis of the future, information technology-based occupations will be important. Although limited Turkish data sources for the analysis of future, results with an accuracy of nearly 1 were produced.