| 1. |
- Emamizadeh, B., et al.
(författare)
-
Optimal harvesting strategy based on rearrangements of functions
- 2018
-
Ingår i: Applied Mathematics and Computation. - Amsterdam : Elsevier. - 0096-3003 .- 1873-5649. ; 320, s. 677-690
-
Tidskriftsartikel (refereegranskat)abstract
- We study the problem of optimal harvesting of a marine species in a bounded domain, with the aim of minimizing harm to the species, under the general assumption that the fishing boats have different capacities. This is a generalization of a result of Kurata and Shi, in which the boats were assumed to have the same maximum harvesting capacity. For this generalization, we need a completely different approach. As such, we use the theory of rearrangements of functions. We prove existence of solutions, and obtain an optimality condition which indicates that the more aggressive harvesting must be pushed toward the boundary of the domain. Furthermore, we prove that radial and Steiner symmetries of the domain are preserved by the solutions. We will also devise an algorithm for numerical solution of the problem, and present the results of some numerical experiments. © 2017 Elsevier Inc.
|
|
| 2. |
- Hierons, Robert M., et al.
(författare)
-
Hardness of deriving invertible sequences from finite state machines
- 2017
-
Ingår i: SOFSEM 2017: SOFSEM 2017: Theory and Practice of Computer Science. - Heidelberg : Springer Berlin/Heidelberg. - 9783319519623 - 9783319519630 ; , s. 147-160
-
Konferensbidrag (refereegranskat)abstract
- Many test generation algorithms use unique input/output sequences (UIOs) that identify states of the finite state machine specification M. However, it is known that UIO checking the existence of UIO sequences is PSPACE-complete. As a result, some UIO generation algorithms utilise what are called invertible sequences; these allow one to construct additional UIOs once a UIO has been found. We consider three optimisation problems associated with invertible sequences: deciding whether there is a (proper) invertible sequence of length at least K; deciding whether there is a set of invertible sequences for state set S′ that contains at most K input sequences; and deciding whether there is a single input sequence that defines invertible sequences that take state set S″ to state set S′. We prove that the first two problems are NP-complete and the third is PSPACE-complete. These results imply that we should investigate heuristics for these problems. © Springer International Publishing AG 2017.
|
|
| 3. |
- Premaratne, Hemakumar Lalith, et al.
(författare)
-
A segmentation-free approach to recognise printed Sinhala script using linear symmetry
- 2004
-
Ingår i: Pattern Recognition. - Amsterdam : Elsevier. - 0031-3203 .- 1873-5142. ; 37:10, s. 2081-2089
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, a novel approach for printed character recognition using linear symmetry is proposed. When the conventional character recognition methods such as the artificial neural network based techniques are used to recognise Brahmi Sinhala script, segmentation of modified characters into modifier symbols and basic characters is a necessity but a complex issue. The large size of the character set makes the whole recognition process even more complex. In contrast, in the proposed method, the orientation features are effectively used to recognise characters directly using a standard alphabet as the basis without the need for segmentation into basic components. The edge detection algorithm using linear symmetry recognises vertical modifiers. The linear symmetry principle is also used to determine the skew angle. Experiments with the aim for an optical character recognition system for the printed Sinhala script show favourable results.
|
|
