Generic Regular Decompositions for Parametric Polynomial Systems

This paper presents a generalization of our earlier work in [19]. In this paper, the two concepts, generic regular decomposition (GRD) and regular-decomposition-unstable (RDU) variety introduced in [19] for generic zero-dimensional systems, are extended to the case where the parametric systems are not necessarily zero-dimensional. An algorithm is provided to compute GRDs and the associated RDU varieties of parametric systems simultaneously on the basis of the algorithm for generic zero-dimensional systems proposed in [19]. Then the solutions of any parametric system can be represented by the solutions of finitely many regular systems and the decomposition is stable at any parameter value in the complement of the associated RDU variety of the parameter space. The related definitions and the results presented in [19] are also generalized and a further discussion on RDU varieties is given from an experimental point of view. The new algorithm has been implemented on the basis of DISCOVERER with Maple 16 and experimented with a number of benchmarks from the literature.Comment: It is the latest version. arXiv admin note: text overlap with arXiv:1208.611

Hierarchical Comprehensive Triangular Decomposition

The concept of comprehensive triangular decomposition (CTD) was first introduced by Chen et al. in their CASC'2007 paper and could be viewed as an analogue of comprehensive Grobner systems for parametric polynomial systems. The first complete algorithm for computing CTD was also proposed in that paper and implemented in the RegularChains library in Maple. Following our previous work on generic regular decomposition for parametric polynomial systems, we introduce in this paper a so-called hierarchical strategy for computing CTDs. Roughly speaking, for a given parametric system, the parametric space is divided into several sub-spaces of different dimensions and we compute CTDs over those sub-spaces one by one. So, it is possible that, for some benchmarks, it is difficult to compute CTDs in reasonable time while this strategy can obtain some "partial" solutions over some parametric sub-spaces. The program based on this strategy has been tested on a number of benchmarks from the literature. Experimental results on these benchmarks with comparison to RegularChains are reported and may be valuable for developing more efficient triangularization tools

Developing a Drought Planning Evaluation System in the United States

Drought is a normal part of the climate cycle, affecting every climate regime on the planet. Drought indicates a special period in which an unusual moisture scarcity causes a serious hydrological imbalance. Drought is related to the timing and effectiveness of the rains, high temperature, high wind, and low humidity. The typical impacts of drought may include dry lands, low or empty water-supply reservoirs, low groundwater levels (dried up wells), crop damage, and ensuing environmental degradation. In the United States, drought accounts for losses in the billions of dollars. In fact, a FEMA (1995) report estimates the average annual losses due to drought at $6-8 billion, on a par with hurricanes, making these the two most costly hazards impacting our country. Drought often affects several sectors (agriculture, recreation and tourism, energy, forestry, and others) at the same time and typically impacts large areas and many people. These impacts serve as indicators of our vulnerability and risk during extended periods of rainfall deficits. Our vulnerability to drought is affected by (among other factors) population growth and shifts, urbanization and sprawl, demographic characteristics, technology, water use trends, government policy, social behavior, and environmental awareness. These factors are continually changing, and society\u27s vulnerability to drought can increase or decrease in response to these changes. Although drought is a natural hazard, society can reduce its vulnerability and therefore lessen the risks associated with drought episodes. The impacts of drought, like those of other natural hazards, can be reduced through mitigation and preparedness. Planning ahead in an attempt to mitigate drought gives decision makers the chance to relieve the most suffering at the least expense. Reacting to drought in crisis mode decreases self-reliance and increases dependence on government and donors (Wilhite and Pulwarty, 2005). As a proof of concept approach, this paper looks into the process of comparing and evaluating state drought plans within the United States. The idea of evaluating (scoring) drought plans may be new, but similar methods have been applied to other hazards and in other planning fields, such as the environmental and urban/rural planning sectors (Baer 1997; Berke 2000; Brody 2003; Tang et a\. 2008). Even so, the planning profession itself has developed relatively few criteria for evaluating the quality of plans, so plan quality is difficult to define (Baer 1997). Now, and in a changing climate with changing vulnerabilities, Brody (2003) aptly notes that planners must be flexible, adapting and planning for changing conditions by gearing their efforts more toward uncertainty and surprise. Thus, the purpose of this paper is to assess the potential transferability of evaluation techniques in other fields and hazards to the evaluation of drought plans in the United States

Developing a Drought Planning Evaluation System in the United States

Drought is a normal part of the climate cycle, affecting every climate regime on the planet. Drought indicates a special period in which an unusual moisture scarcity causes a serious hydrological imbalance. Drought is related to the timing and effectiveness of the rains, high temperature, high wind, and low humidity. The typical impacts of drought may include dry lands, low or empty water-supply reservoirs, low groundwater levels (dried up wells), crop damage, and ensuing environmental degradation. In the United States, drought accounts for losses in the billions of dollars. In fact, a FEMA (1995) report estimates the average annual losses due to drought at $6-8 billion, on a par with hurricanes, making these the two most costly hazards impacting our country. Drought often affects several sectors (agriculture, recreation and tourism, energy, forestry, and others) at the same time and typically impacts large areas and many people. These impacts serve as indicators of our vulnerability and risk during extended periods of rainfall deficits. Our vulnerability to drought is affected by (among other factors) population growth and shifts, urbanization and sprawl, demographic characteristics, technology, water use trends, government policy, social behavior, and environmental awareness. These factors are continually changing, and society\u27s vulnerability to drought can increase or decrease in response to these changes. Although drought is a natural hazard, society can reduce its vulnerability and therefore lessen the risks associated with drought episodes. The impacts of drought, like those of other natural hazards, can be reduced through mitigation and preparedness. Planning ahead in an attempt to mitigate drought gives decision makers the chance to relieve the most suffering at the least expense. Reacting to drought in crisis mode decreases self-reliance and increases dependence on government and donors (Wilhite and Pulwarty, 2005). As a proof of concept approach, this paper looks into the process of comparing and evaluating state drought plans within the United States. The idea of evaluating (scoring) drought plans may be new, but similar methods have been applied to other hazards and in other planning fields, such as the environmental and urban/rural planning sectors (Baer 1997; Berke 2000; Brody 2003; Tang et a\. 2008). Even so, the planning profession itself has developed relatively few criteria for evaluating the quality of plans, so plan quality is difficult to define (Baer 1997). Now, and in a changing climate with changing vulnerabilities, Brody (2003) aptly notes that planners must be flexible, adapting and planning for changing conditions by gearing their efforts more toward uncertainty and surprise. Thus, the purpose of this paper is to assess the potential transferability of evaluation techniques in other fields and hazards to the evaluation of drought plans in the United States

Integrating the principles of strategic environmental assessment into local comprehensive land use plans in California

The lack of early integration with the planning and decision-making process has been a major problem in environmental assessment. Traditional project-based environmental impact assessment has inadequate incentives and capacities to incorporate critical environmental impacts at a broader temporal or spatial scale. While many applications have been geared towards implementing project-level environmental assessments, comparatively little research has been done to determine how to incorporate strategically critical environmental impacts into local planning. Although the principles of strategic environmental assessment (SEA) are not yet required in local planning in the United States, these principles create a theoretical framework for local environmental assessment. The objective of this study is to examine the ability of local plans to integrate and implement the key SEA principles. This study focuses on increasing the understanding of how and where to integrate environmental impacts into the local planning and decision-making process by converting the principles of SEA into specific planning tools, policies, and implementation strategies. This study develops a protocol with 112 indicators to measure the strengths and weaknesses of integrating strategic environmental assessment into local comprehensive land use plans. A random sample of 40 California local comprehensive land use plans and associated planning processes is evaluated based on this plan quality evaluation protocol. Statistical analysis and multiple regression models identify the factors affecting the quality of plans with respect to their ability to assess environmental impacts. The results identify the relative strengths and weaknesses of the ability of local jurisdictions to integrate the SEA principles. The results show that many strategically important environmental issues and tools are rarely adopted by current local plans. The regression analysis results further identify the effects of planning capacity, environmental assessment capacity, public participation and contextual variables on environmental assessment plan quality. The findings extend established planning theory and practice by incorporating strategic environmental considerations into the existing framework of what constitutes a high quality local land use comprehensive plan and suggest ways to improve plan quality

Using Sentinel-2 Imagery and Machine Learning Algorithms to Assess the Inundation Status of Nebraska Conservation Easements during 2018–2021

Conservation easements (CEs) play an important role in the provision of ecological services. This paper aims to use the open-access Sentinel-2 satellites to advance existing conservation management capacity to a new level of near-real-time monitoring and assessment for the conservation easements in Nebraska. This research uses machine learning and Google Earth Engine to classify inundation status using Sentinel-2 imagery during 2018–2021 for all CE sites in Nebraska, USA. The proposed machine learning approach helps monitor the CE sites at the landscape scale in an efficient and low-cost manner. The results confirmed effective inundation performance in these floodplain or wetland-related CE sites. The CE sites under the Emergency Watershed Protection- Floodplain Easement (EWPP-FPE) had the highest inundated area rate of 18.72%, indicating active hydrological inundation in the floodplain areas. The CE sites under the Wetlands Reserve Program (WRP) reached a mean annual surface water cover rate area of 8.07%, indicating the core wetland areas were inundated periodically or regularly. Other types of CEs serving upland conservation purposes had a lower level of inundation while these uplands conservation provided critical needs in soil erosion control. The mean annual surface water cover rate is 0.96% for the CE sites under the Grassland Reserve Program (GRP). The conservation of the CEs on uplands is an important component to reduce soil erosion and improve downstream wetland hydrological inundation performance. The findings support that the sites with higher inundation frequencies can be considered for future wetland-related conservation practices. The four typical wetland-based CE sites suggested that conservation performance can be improved by implementing hydrological restoration and soil erosion reduction at the watershed scale. The findings provided robust evidence to discover the surface water inundation information on conservation assessment to achieve the long-term goals of conservation easements

Long-term (2 years) drying shrinkage evaluation of alkali-activated slag mortar: Experiments and partial factor analysis

Alkali-activated slag with many excellent properties was regarded as a novel low carbon building material, has received more and more attention. This research aims to study the impacts of alkali solution (alkali content and modulus), cement and gypsum contents on compressive strength, weight loss and drying shrinkage for alkali-activated slag mortar. Gypsum used as expanding source could compensate the drying shrinkage caused by silica and alkali components in the first three months, but it has a negative impact on the strength. The mainly results can be concluded that the alkali-activated slag blended with a cement content up to 20 wt% could effectively reduce the shrinkage and weight loss and increase the strength. Furthermore, the alkali content was below 3 wt%, the specimens possess relatively lower drying shrinkage. Based on the results of the test and analysis, the partial factors of combined activation on compressive strength and drying shrinkage of alkali-activated slag mortar were put forward. In the meantime, the relationships between compressive strength and combined activation factor are liner at 28, 90 and 365 days. Compressive strength and drying shrinkage could be estimated according to the combined activation and partial factor analysis. This work could provide a reasonable method for preparing the alkali-activated slag mortar and predict the shrinkage at different periods