Pembentukan Solusi Awal International Timetabling Competition 2021

Penjadawalan olahraga merupakan salah satu cabang dari optimasi di riset operasi. Penjadwalan olahraga memiliki berbagai macam batasan yang menantang para peneliti untuk menyelesaikannya. International Timetabling Competition (ITC) 2021 merupakan salah satu kompetisi optimasi yang menyediakan permasalahan penjadwalan olahraga. Permasalahan utama pada ITC 2021 yaitu menentukan jadwal waktu yang tepat untuk sebuah pertandingan. Sebuah jadwal dikatakan dapat digunakan (feasible) apabila tidak melanggar hard constraint yang ada. Pembentukan solusi awal yang feasible saat ini dapat dilakukan dengan algoritma constraint programming atau integer programming. Akan tetapi, kedua algoritma tersebut cukup rumit untuk diimplementasikan. Penelitian ini berfokus pada pembentukan solusi awal yang feasible dengan cara yang mudah untuk diimplementasikan. Cara yang digunakan yaitu dengan mengoptimasi pelanggaran hard constraint menggunakan algoritma Late Acceptance Hill Climbing (LAHC) dan Tabu Search dengan kerangka kerja Hyper-Heuristic yang melibatkan low level heuristic (LLH). Algoritma dijalankan maksimal dengan batasan waktu 6 jam untuk setiap data. Hasil dari optimasi pelanggaran hard constraint menggunakan algoritma LAHC dan tabu search dapat menghasilkan solusi awal yang feasible sebanyak 44.44% atau 24 dari 54 keseluruhan dataset.

HEURISTIC OPTIMIZATION OF THE FOUNDATION OF A DYNAMICALLY STRESSED ROTATING MACHINE USING THE LATE ACCEPTANCE HILL CLIMBING (LAHC) ALGORITHM

This paper proposal the optimization of a foundation for rotative machine under dynamic loads in transient and permanent working mode. The foundation depends on fix parameters and 37 variables. Functional constraints are defined for the foundation. A cost function depending on the variables is defined to be minimized to find the optimal. From all the possible solutions, only are selected the ones that validate the constrains and minimize the cost function. The search of the optimal solution is made with an algorithm of random search by “neighbouring of one point” called Last Acceptance Hill Climbing(LAHC). It is an algorithm of the type called “Adaptative Memory Programming” (AMP) that accepts worse solutions to get the local minimum and learns of the results of the search. The algorithm only depends on the length of the comparison vector and the stop criteria. 350 experiences were made with different length of the comparison vector. It was analysed the quality of the optimal solutions got it with each length of the vector. Quality of the set of solutions was compared fitting them to a 3 parameters Weibull distribution.

Path Planning for Indoor UAV Using A* and Late Acceptance Hill Climbing Algorithms Utilizing Probabilistic Roadmap

The main objective of an unmanned aerial vehicle (UAV) path planning is to generate a flight path that links a start point to an endpoint in an indoor space avoiding obstacles. Path planning is essential for many real-life applications such as an autonomous car, surveillance mission, farming robots, unmanned aerial vehicles package delivery, space exploration, and many others. To create an optimal path, we need to adopt a specific criterion to minimize the distance the UAV must travel such as the Euclidean distance. In this paper, we provide our initial idea of creating an optimal path for indoor UAV using both A* and the Late Acceptance Hill Climbing (LAHC) algorithms. We are adopting an indoor search environment with various complexity and utilize the Probabilistic Roadmap algorithm (PRM) as a search space for both algorithms. The basic idea following PRM is to generate random sample points in the space and search these points for an optimal path. The developed results show that the LAHC algorithm outperforms the A* algorithm.

Late Acceptance Hill-Climbing Matheuristic for the General Lot Sizing and Scheduling Problem with Rich Constraints

This paper considers the general lot sizing and scheduling problem with rich constraints exemplified by means of rework and lifetime constraints for defective items (GLSP-RP), which finds numerous applications in industrial settings, for example, the food processing industry and the pharmaceutical industry. To address this problem, we propose the Late Acceptance Hill-climbing Matheuristic (LAHCM) as a novel solution framework that exploits and integrates the late acceptance hill climbing algorithm and exact approaches for speeding up the solution process in comparison to solving the problem by means of a general solver. The computational results show the benefits of incorporating exact approaches within the LAHCM template leading to high-quality solutions within short computational times.