Search results for " search"

A Maximal-Space Algorithm for the Container Loading Problem

2008

In this paper, a greedy randomized adaptive search procedure (GRASP) for the container loading problem is presented. This approach is based on a constructive block heuristic that builds upon the concept of maximal space, a nondisjoint representation of the free space in a container. This new algorithm is extensively tested over the complete set of Bischoff and Ratcliff problems [Bischoff, E. E., M. S. W. Ratcliff. 1995. Issues in the development of approaches to container loading. Omega 23 377–390], ranging from weakly heterogeneous to strongly heterogeneous cargo, and outperforms all the known nonparallel approaches that, partially or completely, have used this set of test problems. When …

A New Metaheuristic for the Vehicle Routing Problem with Split Demands

2007

In this paper we present a metaheuristic procedure constructed for the special case of the Vehicle Routing Problem in which the demands of the clients can be split, i.e., any client can be serviced by more than one vehicle. The proposed algorithm, based on the scatter search methodology, produces a feasible solution using the minimum number of vehicles. The results obtained compare with the best results known up to date on a set of instances previously published in the literature.

Efficient Local Search Limitation Strategies for Vehicle Routing Problems

2008

In this paper we examine five different strategies for limiting the local search neighborhoods in the context of vehicle routing problems. The vehicle routing problem deals with the assignment of a set of transportation orders to a fleet of vehicles, and the sequencing of stops for each vehicle to minimize transportation costs. The examined strategies are applied to three standard neighborhoods and implemented in a recently suggested powerful memetic algorithm. Experimental results on 26 well-known benchmark problems indicate significant speedups of almost 80% without worsening the solution quality. On the contrary, in 12 cases new best solutions were obtained.

Scatter Search and Path-Relinking: Fundamentals, Advances, and Applications

2010

Scatter search is an evolutionary metaheuristic that explores solution spaces by evolving a set of reference points, operating on a small set of solutions while making only limited use of randomization. We give a comprehensive description of the elements and methods that make up its template, including the most recent elements incorporated in successful applications in both global and combinatorial optimization. Path-relinking is an intensification strategy to explore trajectories connecting elite solutions obtained by heuristic methods such as scatter search, tabu search, and GRASP. We describe its mechanics, implementation issues, randomization, the use of pools of high-quality solutions …

Content Based Indexing of Image and Video Databases by Global and Shape Features

1996

Indexing and retrieval methods based on the image content are required to effectively use information from the large repositories of digital images and videos currently available. Both global (colour, texture, motion, etc.) and local (object shape, etc.) features are needed to perform a reliable content based retrieval. We present a method for automatic extraction of global image features, like colour and motion parameters, and their use for data restriction in video database querying. Further retrieval is therefore accomplished, in a restricted set of images, by shape feature (skeleton, local symmetry moments, correlation, etc.) local search. The proposed indexing methodology has been deve…

Quantum planning for swarm robotics

2023

Computational resources of quantum computing can enhance robotic motion, decision making, and path planning. While the quantum paradigm is being applied to individual robots, its approach to swarms of simple and interacting robots remains largely unexplored. In this paper, we attempt to bridge the gap between swarm robotics and quantum computing, in the framework of a search and rescue mission. We focus on a decision-making and path-planning collective task. Thus, we present a quantum-based path-planning algorithm for a swarm of robots. Quantization enters position and reward information (measured as a robot’s proximity to the target) and path-planning decisions. Pairwise information-exchan…

U-MedSearch: A Meta Search Engine of Medical Content for Different Users and Learning Needs

2015

More and more people use Internet to look for medical information for understanding and learning but different users, such as experts (e.g., physicians) and consumers (e.g., patients), have different needs and bring different levels of reading ability and prior knowledge. Generic and specific search engines and specialized health sites either do not exploit the whole web or overload users with information of different nature. On the contrary, it is important for a user to immediately find the information on the topic being explored that has the 'right' amount of information and level of complexity. This paper presents a meta search engine of medical information on the web, U-MedSearch, that…

Finding the best web medical content for different learner categories

2015

In the age of Internet where any kind of information can be easily found online, it is becoming increasingly evident that more and more people use the World Wide Web to seek health and medical information for understanding and learning. Different users have diverse needs, even when searching for the same topic. This is certainly true in healthcare, where a patient, a physician or a health executive might look for information on the same topic but have different necessities and bring different levels of reading ability and prior knowledge together with a different vocabulary. Generic search engines (like Google, Bing or Yahoo) work on the whole web but make generic searches often overloading…

Indexed Two-Dimensional String Matching

2016

STUDIO DI UNA FRIZIONE MAGNETOREOLOGICA PER AUTOVEICOLI

2013

Dopo un’accurata ricerca bibliografica sui fluidi magnetoreologici, il loro comportamento ed impiego, si è passati alla progettazione di una frizione magnetoreologica per autoveicoli. Considerando le caratteristiche di coppia trasmessa e potenza, il dispositivo è stato dimensionato tenendo presente i vincoli di ingombro del veicolo preso in esame. Sottoponendo il dispositivo ad analisi magnetostatica agli elementi finiti, si è determinato l’andamento delle linee di flusso del campo magnetico nel meato di fluido e nelle zone di maggior interesse, calcolando la coppia teoricamente trasmessa dall’innesto.È stato anche eseguito il confronto delle prestazionifra una frizione MR ed una frizione t…