Local-Search Based Heuristics for Advertisement Scheduling

In the MAXSPACE problem, given a set of ads A, one wants to place a subset A' of A into K slots B_1, ..., B_K of size L. Each ad A_i in A has size s_i and frequency w_i. A schedule is feasible if the total size of ads in any slot is at most L, and each ad A_i in A' appears in exactly w_i slots. The goal is to find a feasible schedule that maximizes the space occupied in all slots. We introduce MAXSPACE-RDWV, a MAXSPACE generalization with release dates, deadlines, variable frequency, and generalized profit. In MAXSPACE-RDWV each ad A_i has a release date r_i >= 1, a deadline d_i >= r_i, a profit v_i that may not be related with s_i and lower and upper bounds w^min_i and w^max_i for frequency. In this problem, an ad may only appear in a slot B_j with r_i <= j <= d_i, and the goal is to find a feasible schedule that maximizes the sum of values of scheduled ads. This paper presents some algorithms based on meta-heuristics GRASP, VNS, Local Search, and Tabu Search for MAXSPACE and MAXSPACE-RDWV. We compare our proposed algorithms with Hybrid-GA proposed by Kumar et al. (2006). We also create a version of Hybrid-GA for MAXSPACE-RDWV and compare it with our meta-heuristics. Some meta-heuristics, such as VNS and GRASP+VNS, have better results than Hybrid-GA for both problems. In our heuristics, we apply a technique that alternates between maximizing and minimizing the fullness of slots to obtain better solutions. We also applied a data structure called BIT to the neighborhood computation in MAXSPACE-RDWV and showed that this enabled ours algorithms to run more iterations

Approximation algorithms for the MAXSPACE advertisement problem

In the MAXSPACE problem, given a set of ads A, one wants to schedule a subset A' of A into K slots B_1, ..., B_K of size L. Each ad A_i in A has a size s_i and a frequency w_i. A schedule is feasible if the total size of ads in any slot is at most L, and each ad A_i in A' appears in exactly w_i slots. The goal is to find a feasible schedule that maximizes the sum of the space occupied by all slots. We introduce a generalization called MAXSPACE-R in which each ad A_i also has a release date r_i >= 1, and may only appear in a slot B_j with j >= r_i. We also introduce a generalization of MAXSPACE-R called MAXSPACE-RD in which each ad A_i also has a deadline d_i <= K, and may only appear in a slot B_j with r_i <= j <= d_i. These parameters model situations where a subset of ads corresponds to a commercial campaign with an announcement date that may expire after some defined period. We present a 1/9-approximation algorithm for MAXSPACE-R and a polynomial-time approximation scheme for MAXSPACE-RD when K is bounded by a constant. This is the best factor one can expect, since MAXSPACE is NP-hard, even if K = 2

Carbon content in sandy soils under different use and management systems.

Quantifying soil carbon content is important to assess soil indicators related to adequate management conducted by producers in their agricultural systems. The objective of this study was to evaluate the total soil carbon content in soils under different use and management systems

Carbon content in sandy soils under different use and management systems.

Quantifying soil carbon content is important to assess soil indicators related to adequate management conducted by producers in their agricultural systems. The objective of this study was to evaluate the total soil carbon content in soils under different use and management systems

Gestão do uso e conservação de água em sistemas pecuários no Cerrado.

A utilização da água nas propriedades rurais deve estar adequada com a "Lei das Águas". O aproveitamento do potencial hídrico das propriedades envolve diratamente às práticas conservacionistas como manutenção da cobertura vegetal nas margens das fontes de água e uso e manejo adequado do solo. Neste trabalho fazemos algumas sugestões para que o proprietário seja aliado na conservação ambiental, tornando-se um "produtor de água".bitstream/item/104774/1/Gestao-do-uso-e-conservacao.pd

Composicao botanica da dieta de bubalinos na Nhecolandia, Pantanal Sul-Mato-Grossense.

Como alternativa para o incremento da pecuaria de corte no Pantanal, o bufalo Bubalus bubalis, apresenta-se como um potencial favoravel devido a sua rusticidade e adaptabilidade aos ambientes da planicie pantaneira. Visando avaliar o aproveitamento das forrageiras nativas da sub-regiao da Nhecolandia pelos bubalinos, utilizou-se a tecnica microhistologica de analise fecal (Hansen et al., 1971). Foram identificadas 53 especies nativas que mais contribuem na dieta dessa especie na sub-regiao. Os locais com maior incidencia de pastejo foram: campos altos e cordilheiras (ambos com 34%), campo inundavel (17%) e baia (15%). Axonopus purpusii e Elyonurus muticus sao predominantes nas pastagens e contribuem muito na dieta. E. muticus e caracterizado por ser rejeitada pelo gado bovino independente do estadio de maturacao. O bufalo, por ser capaz de digerir material fibroso, apresenta boa perspectiva de ocupacao dos caronais.bitstream/item/79367/1/COT09.pd

A realidade bioeconômica do médio pecuarista: um estudo de caso em Mato Grosso do Sul.

Base conceitual. O estudo de caso em Mato Grosso.bitstream/item/132188/1/Doc154.pd

Teores de carbono em um neossolo sob diferentes manejos e uso no cerrado do Mato Grosso do Sul.

A quantificação dos teores de carbono (C) no solo é um indicativo importante para se avaliar o manejo do solo. Os grandes estoques de carbono na Terra estão nos oceanos, atmosfera, nas formações geológicas com carbono fóssil e mineral, e nos ecossistemas terrestres: biota e solo. Esta realidade impõe às atividades agrícolas uma grande responsabilidade quanto ao manejo do solo, principalmente no sentido de manter esse reservatório como um grande trunfo frente à emissão de gases do efeito estufa (GEEs). O objetivo deste trabalho foi avaliar os teores de C total e as respectivas densidades do solo (Ds)em três sistemas de uso e manejo do solo, a saber: floresta de eucalipto, pastagem degradada e vegetação nativa