Please wait, while we are loading the content...
Please wait, while we are loading the content...
| Content Provider | Springer Nature Link |
|---|---|
| Author | Caprara, Alberto Monaci, Michele |
| Copyright Year | 2007 |
| Abstract | We consider geometric problems in which rectangles have to be packed into (identical) squares. These problems turn out to be very hard in practice, and ILP formulations in which variables specify the coordinates in the packing perform very poorly. While most methods developed so far are based on simple geometric considerations, a recent landmark result of Fekete and Schepers suggests to put these geometric aspects aside and use the most advanced tools for the one-dimensional case. In this paper we make additional progress in this direction, especially on the basic question “Does a given set of rectangles fit into a square?”, which turns out to be the bottleneck of all the approaches known. Given a set of rectangles and the associated convex hull of rectangle subsets that fit into a square, we derive a wide class of valid inequalities for this convex hull from a complete description of the two knapsack polytopes associated with the widths and the heights of the rectangles, respectively. In addition, we illustrate how to solve the associated separation problem as a bilinear program, for which we develop a solution method that turns out to be fast in practice, and show that the integer solutions that satisfy all these constraints generally correspond to vertices of the original convex hull for the benchmark instances in the literature. The same tools are used to derive lower bounds for the two-dimensional bin packing problem, corresponding to the determination of an optimal pair of so-called dual feasible functions. These lower bounds in many cases equal those obtained by the customary set covering formulation (for which column generation is very hard), but are computable within a time that is smaller by some orders of magnitude. This allows us to close a few of the benchmark instances in the literature. |
| Ending Page | 108 |
| Page Count | 34 |
| Starting Page | 75 |
| File Format | |
| ISSN | 00255610 |
| e-ISSN | 14364646 |
| Journal | Mathematical Programming |
| Issue Number | 1 |
| Volume Number | 118 |
| Language | English |
| Publisher | Springer-Verlag |
| Publisher Date | 2007-08-30 |
| Publisher Place | Berlin, Heidelberg |
| Access Restriction | One Nation One Subscription (ONOS) |
| Subject Keyword | Packing and covering in $2$ dimensions Mathematical Methods in Physics Dual feasible functions Mathematics of Computing Calculus of Variations and Optimal Control; Optimization Mathematical and Computational Physics Numerical Analysis Bidimensional packing Computational experiments Bilinear programming Combinatorics |
| Content Type | Text |
| Resource Type | Article |
| Subject | Mathematics Software |
National Digital Library of India (NDLI) is a virtual repository of learning resources which is not just a repository with search/browse facilities but provides a host of services for the learner community. It is sponsored and mentored by Ministry of Education, Government of India, through its National Mission on Education through Information and Communication Technology (NMEICT). Filtered and federated searching is employed to facilitate focused searching so that learners can find the right resource with least effort and in minimum time. NDLI provides user group-specific services such as Examination Preparatory for School and College students and job aspirants. Services for Researchers and general learners are also provided. NDLI is designed to hold content of any language and provides interface support for 10 most widely used Indian languages. It is built to provide support for all academic levels including researchers and life-long learners, all disciplines, all popular forms of access devices and differently-abled learners. It is designed to enable people to learn and prepare from best practices from all over the world and to facilitate researchers to perform inter-linked exploration from multiple sources. It is developed, operated and maintained from Indian Institute of Technology Kharagpur.
Learn more about this project from here.
NDLI is a conglomeration of freely available or institutionally contributed or donated or publisher managed contents. Almost all these contents are hosted and accessed from respective sources. The responsibility for authenticity, relevance, completeness, accuracy, reliability and suitability of these contents rests with the respective organization and NDLI has no responsibility or liability for these. Every effort is made to keep the NDLI portal up and running smoothly unless there are some unavoidable technical issues.
Ministry of Education, through its National Mission on Education through Information and Communication Technology (NMEICT), has sponsored and funded the National Digital Library of India (NDLI) project.
| Sl. | Authority | Responsibilities | Communication Details |
|---|---|---|---|
| 1 | Ministry of Education (GoI), Department of Higher Education |
Sanctioning Authority | https://www.education.gov.in/ict-initiatives |
| 2 | Indian Institute of Technology Kharagpur | Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project | https://www.iitkgp.ac.in |
| 3 | National Digital Library of India Office, Indian Institute of Technology Kharagpur | The administrative and infrastructural headquarters of the project | Dr. B. Sutradhar bsutra@ndl.gov.in |
| 4 | Project PI / Joint PI | Principal Investigator and Joint Principal Investigators of the project |
Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon |
| 5 | Website/Portal (Helpdesk) | Queries regarding NDLI and its services | support@ndl.gov.in |
| 6 | Contents and Copyright Issues | Queries related to content curation and copyright issues | content@ndl.gov.in |
| 7 | National Digital Library of India Club (NDLI Club) | Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach | clubsupport@ndl.gov.in |
| 8 | Digital Preservation Centre (DPC) | Assistance with digitizing and archiving copyright-free printed books | dpc@ndl.gov.in |
| 9 | IDR Setup or Support | Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops | idr@ndl.gov.in |
|
Loading...
|