An Algorithm for Infinite Horizon Lot Sizing with Deterministic Demand

We analyze an infinite horizon discrete time inventory model with deterministic but non-stationary demand for a single product at a single stage. There is a finite cycle of vectors of characteristics of the environment (demand, fixed ordering cost, variable procurement cost, holding cost) which is repeated after a finite number of periods. Future cost is discounted. In general, minimization of the sum of discounted total cost over the cycle does not give the minimum of the sum of discounted total cost over the infinite horizon. We construct an algorithm for computing of an optimal strategy over the infinite horizon. It is based on a forward in time dynamic programming recursion.

Analysis of Dynamic Changes in Habitat Quality Based on InVEST Models:A Case Study of Pu er City,Yunnan Province

Based on the data of land use status in 2009-2018 in the annual change survey results of Pu er City,Yunnan Province,China,the habitat quality in the city were studied by using InVEST models.The results show that the area of cultivated land,construction land,and unused land in Pu er City continuously increased from 2009 to 2018.The growth rate of cultivated land and construction land in the next three years was significantly higher than that in the previous three years,while the area of gardens,grassland and woodland continuously decreased.From 2009 to 2018,the habitat quality in Pu er City showed a downward trend,that is,there was a clear increase in the proportion of moderate and poor habitat quality and a decrease in the proportion of superior and good habitat quality.Changes in habitat quality calculated by InVEST models can be used as a grasp of regional ecological environment in the investigation before the audit of natural resource assets and breakthroughs in finding clues of problems,thereby improving the scientificity and efficiency of audit work of natural resource assets.

Ecotourism Development and Biodiversity Conservation in Sri Lanka: Objectives, Conflicts and Resolutions

Biodiversity conservation and sustainably utilizing natural resources improve the benefits of ecotourism development. Ecotourism development makes values for sustainably using biodiversity creating economic development opportunities. This study reviews literature and reveals objectives, conflicts and resolutions for achieving biodiversity conservation through ecotourism development in Sri Lanka. This paper describes conservation objectives in terms of preserving and fostering biodiversity, habitat restoration and managing biodiversity, and making values for natural assets through ecotourism activities. Degradation and destruction of habitat, overexploitation and illegal extraction of species, emissions of greenhouse gasses for climate change, contamination and pollution of the environment, and spread of exotic species are identified as the main conflicts. Conservation resolutions are discussed on education and awareness-raising activities for biodiversity conservation, in-situ conservation and ex-situ preservation of species, integrating biodiversity into ecotourism development, integrating management of biodiversity and ecotourism, linking ecotourism industry and conservation organizations, ecotourism policy and legislations for biodiversity conservation, and imposition of rules and regulations. Policy solutions and building capacity among institutions and other stakeholders for governance and sustainable conservation of biodiversity are key for sustainable ecotourism development.

Assessing the effectiveness of protecting reserves for nature assets in China

Evaluating the effectiveness of protecting nature assets is a vital component of responsive, pro-active management of protected areas. It is important to protect reserves of geological （including fossils） assets as a means to also protect national and natural heritage. At the end of 2013, 2669 protected areas had been established in China and 123 of them are reserves for nature assets. This paper builds an evaluation framework for protection effectiveness of these assets. The current elements and characteristics for effective protection are analyzed, along with an analysis of existing problems so as to construct a scientific approach to protect these assets. The influencing elements and characteristics for effective protection of nature asset reserves are included in an index evaluation system for effective protection in such areas, which contains four parts-target layer, evaluation criteria, evaluation indexes, and evaluation parameters-based on related documents and files. For the target layer, it includes nature asset evaluation and management evaluation. In the end, it is discussed how to build a comprehensive evaluation model and achieve an effective quantitative evaluation.