Effects of shade level and microenvironment on vegetative growth, physiological and biochemical characteristics of transplanted cucumber (Cucumis sativus)

Growing vegetables through transplantation under black shade nets is currently becoming popular to provide protection from high intensities of light and high temperatures. This study evaluated the effects of shade level on microenvironment, vegetative growth, photosynthetic pigments, chlorophyll a fluorescence, osmoprotectants, plant water status and leaf mineral nutrients of greenhouse-grown summer cucumber transplants at 25%, 50%, 63%, and 75% shade levels. Solar radiation and tempera-ture decreased with increased shading levels. Average daily temperatures were approximately decreased by 1.5oC under 75% shade nets compared to the 25% shade nets. Vegetative growth characteristics, photosynthetic pigments, chlorophyll a fluorescence (Fv/Fm, Fv/F0, and PI), dehydration tolerance and Leaf N, P and K concentrations increased when shade level increased. Chlorophyll a fluorescence (Fv/Fm, Fv/F0, and PI) reduced with the increase of solar radiation levels. Also, clear decreases in free proline, soluble sugars and total free amino acids in both experiments with increased shade level have been observed. Additionally, relative water content (RWC), membrane stability index (MSI) and electrolyte leakage (EL) of cucumber transplants were significantly affected in both experiments by shade level. Moreover Shade level affected leaf mineral nutrient but the effect differed among nutrients concentration. This study concluded that, nets with higher shading levels (63 and/or 75%) are a potential alternative to alleviate photo-inhibition and heat stress in cucumber transplants production

29th Annual International INCOSE Symposium

Asset planning is a complex and dynamic problem, where the decision maker is often faced with the challenge of making decisions now about aspects that will change over the asset lifetime. This paper is a part of an ongoing study whose goal is to develop decision‐support methods and tools (qualitative and quantitative) to support asset planning. In this context, this paper's objective is to demonstrate an integrated approach for combining System Dynamics (SD) and Multi‐criteria Decision‐Making (MCDM). To support the design approach, the paper uses a multi‐method design framework, from the wider Operations Research/Management Science (OR/MS) literature, as a theoretical lens to review and synthesize literature. To apply and test this approach in practice, the paper uses as a test case the classic asset replacement problem from the asset management literature. The test case is applied in a real‐life decision support project for fleet planning in a military organization. Results showcase the value of using SD (qualitative and quantitative) methods and MCDM, both independently and integrated, to support asset planning

MODSIM 2017: Managing cumulative risks through model-based processes

The decision making of complex systems is challenging because of the presence of non-linearities and time delays in their structure and their behaviour. This decision making over the system lifetime is also challenged by the presence of deep uncertainty in the future behaviour of systems and in their surrounding environment. Traditional modelling approaches are inclined to consolidate all facts into a single ultimate model and to take a deterministic, optimal and predictive approach in decision making. However, they proved to be inadequate for coping with complexity and uncertainty challenges. We argue that an exploratory multi-method approach to modelling is needed for making effective and robust decisions for complex systems; the decisions which remain valid under a diverse range of future conditions. This paper illustrates the combined use of multi-method modelling and exploratory analysis in the support of complex systems decision making, with an application to asset acquisition and management and using the case of aircraft fleet as an illustrative example. First, a framework is introduced for the implementation of this multi-method exploratory approach in practice, and the model structure, developed for the case of aircraft fleet, is explained. We then discuss how the use of our new approach can improve the robustness of decisions in asset acquisition and management. An initial exploratory analysis is performed on the model under deep uncertainty conditions and with three design strategies: High Acquisition – Low Maintenance, Low Acquisition – High Maintenance, and Medium Acquisition – Medium Maintenance. The analysis of the results shows that investing on the maintenance capacity of an aircraft fleet could result in more average flying hours compared to more acquisition of new aircraft. However, this could cause two side-effects: a higher total (acquisition and maintenance) costs and a wider uncertainty in the future performance of the system (in terms of average flying hours and total costs)

Predicting water quality responses to a changing climate: building an integrated modelling framework

The future management of freshwater resources for human and environmental needs requires an integrated set of tools for predicting the relationship between climate change, water quality and ecological responses. In this paper, we present the early phase