734 research outputs found
A single-machine scheduling problem with multiple unavailability constraints: A mathematical model and an enhanced variable neighborhood search approach
AbstractThis research focuses on a scheduling problem with multiple unavailability periods and distinct due dates. The objective is to minimize the sum of maximum earliness and tardiness of jobs. In order to optimize the problem exactly a mathematical model is proposed. However due to computational difficulties for large instances of the considered problem a modified variable neighborhood search (VNS) is developed. In basic VNS, the searching process to achieve to global optimum or near global optimum solution is totally random, and it is known as one of the weaknesses of this algorithm. To tackle this weakness, a VNS algorithm is combined with a knowledge module. In the proposed VNS, knowledge module extracts the knowledge of good solution and save them in memory and feed it back to the algorithm during the search process. Computational results show that the proposed algorithm is efficient and effective
Swarm intelligence for scheduling: a review
Swarm Intelligence generally refers to a problem-solving ability that emerges from the
interaction of simple information-processing units. The concept of Swarm suggests multiplicity,
distribution, stochasticity, randomness, and messiness. The concept of Intelligence suggests that
problem-solving approach is successful considering learning, creativity, cognition capabilities. This paper
introduces some of the theoretical foundations, the biological motivation and fundamental aspects of
swarm intelligence based optimization techniques such Particle Swarm Optimization (PSO), Ant Colony
Optimization (ACO) and Artificial Bees Colony (ABC) algorithms for scheduling optimization
Energy aware hybrid flow shop scheduling
Only if humanity acts quickly and resolutely can we limit global warming' conclude more than 25,000 academics with the statement of SCIENTISTS FOR FUTURE. The concern about global warming and the extinction of species has steadily increased in recent years
Pengembangan Algoritma Biogeography-based Optimization (BBO) Untuk Penyelesaian Single Machine Total Weighted Tardiness Problem (SMTWTP)
Permasalahan penjadwalan adalah salah satu permasalahan populer yang masih banyak diteliti. Salah satu masalah penjadwalan dasar adalah Single Machine Total weighted Tardiness Problem (SMTWTP). Permasalahan tersebut termasuk NP-hard sehingga tidak sesuai untuk diselesaikan dengan metode eksak. Saat ini telah banyak berkembang metode metaheuristik yang mampu memberikan solusi cukup bagus untuk permasalahn NP-hard. Salah satu metode metaheuristik baru yang mengadaptasi fenomena biogeografi adalah Biogeography-based Optimization (BBO). Algoritma BBO diketahui memiliki performansi yang cukup bagus untuk permasalahan kontinyu. Pada penelitian ini dikembangkan sebuah algoritma BBO untuk menyelesaikan permasalahan diskrit yaitu SMTWTP. Dalam penelitian ini BBO mampu mencapai 57 nilai optimal dari 75 kasus berbeda. BBO memiliki performansi yang lebih baik dari Particle Swarm Optimization dengan 19 nilai optimal tetapi tidak lebih baik dibandingkan dengan Genetic Algorithm modifikasi yang mampu mencapai 67 nilai optimal
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An intelligent manufacturing system for heat treatment scheduling
This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This research is focused on the integration problem of process planning and scheduling in steel heat treatment operations environment using artificial intelligent techniques that are capable of dealing with such problems.
This work addresses the issues involved in developing a suitable methodology for scheduling heat treatment operations of steel. Several intelligent algorithms have been developed for these propose namely, Genetic Algorithm (GA), Sexual Genetic Algorithm (SGA), Genetic Algorithm with Chromosome differentiation (GACD), Age Genetic Algorithm (AGA), and Mimetic Genetic Algorithm (MGA). These algorithms have been employed to develop an efficient intelligent algorithm using Algorithm Portfolio methodology. After that all the algorithms have been tested on two types of scheduling benchmarks.
To apply these algorithms on heat treatment scheduling, a furnace model is developed for optimisation proposes. Furthermore, a system that is capable of selecting the optimal heat treatment regime is developed so the required metal properties can be achieved with the least energy consumption and the shortest time using Neuro-Fuzzy (NF) and Particle Swarm Optimisation (PSO) methodologies. Based on this system, PSO is used to optimise the heat treatment process by selecting different heat treatment conditions. The selected conditions are evaluated so the best selection can be identified. This work addresses the issues involved in developing a suitable methodology for developing an NF system and PSO for mechanical properties of the steel.
Using the optimisers, furnace model and heat treatment system model, the intelligent system model is developed and implemented successfully. The results of this system were exciting and the optimisers were working correctly
Bütünleşik tedarik zinciri çizelgeleme modelleri: Bir literatür taraması
Research on integration of supply chain and scheduling is relatively recent, and
number of studies on this topic is increasing. This study provides a comprehensive
literature survey about Integrated Supply Chain Scheduling (ISCS) models to help
identify deficiencies in this area. For this purpose, it is thought that this study will
contribute in terms of guiding researchers working in this field. In this study,
existing literature on ISCS problems are reviewed and summarized by introducing
the new classification scheme. The studies were categorized by considering the
features such as the number of customers (single or multiple), product lifespan
(limited or unlimited), order sizes (equal or general), vehicle characteristics
(limited/sufficient and homogeneous/heterogeneous), machine configurations and
number of objective function (single or multi objective). In addition, properties of
mathematical models applied for problems and solution approaches are also
discussed.Bütünleşik Tedarik Zinciri Çizelgeleme (BTZÇ) üzerine yapılan araştırmalar
nispeten yenidir ve bu konu üzerine yapılan çalışma sayısı artmaktadır. Bu çalışma,
bu alandaki eksiklikleri tespit etmeye yardımcı olmak için BTZÇ modelleri hakkında
kapsamlı bir literatür araştırması sunmaktadır. Bu amaçla, bu çalışmanın bu alanda
çalışan araştırmacılara rehberlik etmesi açısından katkı sağlayacağı
düşünülmektedir. Bu çalışmada, BTZÇ problemleri üzerine mevcut literatür gözden
geçirilmiş ve yeni sınıflandırma şeması tanıtılarak çalışmalar özetlenmiştir.
Çalışmalar; tek veya çoklu müşteri sayısı, sipariş büyüklüğü tipi (eşit veya genel),
ürün ömrü (sınırlı veya sınırsız), araç karakteristikleri (sınırlı/yeterli ve
homojen/heterojen), makine konfigürasyonları ve amaç fonksiyonu sayısı (tek veya
çok amaçlı) gibi özellikler dikkate alınarak kategorize edildi. Ayrıca problemler için
uygulanan matematiksel modellerin özellikleri ve çözüm yaklaşımları da
tartışılmıştır
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