Determining the Optimal Density of Phoebe bournei Plantations Based on Dynamic Programming under Close-to-Nature Management Measures

Close-to-nature management (CTNM) is the most promising option for plantation silviculture and has received widespread attention in recent years. Stand density is a key variable in CTNM, as it directly influences growth and yield. Research for the optimal density that maximizes the total harvest has been ongoing. In this paper, a dynamic programming model was applied to the CTNM of Phoebe bournei plantations for the first time to solve the problem of stand density and target tree density control. This paper took Phoebe bournei plantations in Jindong Forest Farm of Hunan Province as the research object. Based on the data of seven consecutive years from 2015 to 2021, Richard’s growth equation was used to fit the height growth equation and basal area growth equation of Phoebe bournei. Stand growth was divided into five development stages according to the forest growth process and characteristics. Stand density and basal area were selected as two-dimensional state variables, and the maximum total harvest in the entire stand growth process was used as the objective function to establish a dynamic programming model. The optimal stand density and target tree density at each growth stage of the stand under three different site conditions were determined. According to the results obtained, the objective forest shape was designed for the stand under three types of site conditions, which can provide a theoretical basis for the CTNM of Phoebe bournei plantations to make the stand achieve the maximum harvest.

Hybrid Transshipment Policy and Ordering Model for Multiple Periods with Customer Switching Behaviour

The interaction of a hybrid transshipment policy and customer switching behaviour will exacerbate the complexity of the structure of a hybrid transshipment policy. To cope with this problem, a discrete-time dynamic programming model framework with customer switching behaviour is developed. Based on this framework, we demonstrate that the retailer can obtain more profits with a hybrid transshipment than without one. Next, the existence of a reactive and preventive transshipment policy is shown, respectively. We further analyse the structural property of the holdback policy of reactive transshipment and give the threshold of customer switching rate when always rejecting the request. Meanwhile, a dominant preventive transshipment policy is formulated by which the retailer can control the inventory regardless of the influence of the preventive transshipment policy of the other as long as the inventory is observed by developing an easy-to-implement optimal hybrid transshipment strategy. In addition, the existence of an ordering Nash equilibrium of two retailers is proven. Then, we also illustrate the existence of a transshipment area and analyse the impact of the transshipment cost and switching rate on ordering, the hybrid transshipment policy, and profit by using numerical examples. Finally, we find that the retailer is more willing to adjust inventory by ordering when there is a lower transshipment price and adjust inventory by hybrid transshipment when there is a higher transshipment price.

A Real Options Approach to Design for Quality Standards Considering Life Cycle of a Product

Flexibility is recognized as a valuable parameter for a manufacturing system. When valuing flexibility for quality standards of a production facility, there must be a tool to precisely justify the value delivered by the preferred standards. In this project, we have developed an options model that accounts for the demand dynamics during the product life cycle. We consider a manufacturing facility that employs a specific quality control chart. A second control chart with more strict standards is generated and the effectiveness of two control charts is analyzed with options framework considering the life cycle of the product. The options model is evaluated by lattice approach and the dynamic programming model. The results show that a set of appropriate levels of quality standards when adopted by a manufacturing system can be profitable for the firm.

A Real Options Approach to Design for Quality Standards Considering Life Cycle of a Product

Flexibility is recognized as a valuable parameter for a manufacturing system. When valuing flexibility for quality standards of a production facility, there must be a tool to precisely justify the value delivered by the preferred standards. In this project, we have developed an options model that accounts for the demand dynamics during the product life cycle. We consider a manufacturing facility that employs a specific quality control chart. A second control chart with more strict standards is generated and the effectiveness of two control charts is analyzed with options framework considering the life cycle of the product. The options model is evaluated by lattice approach and the dynamic programming model. The results show that a set of appropriate levels of quality standards when adopted by a manufacturing system can be profitable for the firm.