Estimation of heterogeneous aquifer parameters using centralized and decentralized fusion of hydraulic tomography data

Characterization of spatial variability of hydraulic properties of groundwater systems at high resolution is essential to simulate flow and transport phenomena. This paper investigates two schemes to invert transient hydraulic head data resulting from multiple pumping tests for the purpose of estimating the spatial distributions of the hydraulic conductivity, K, and the specific storage, Ss, of an aquifer. The two methods are centralized fusion and decentralized fusion. The centralized fusion of transient data is achieved when data from all pumping tests are processed concurrently using a central inversion processor, whereas the decentralized fusion inverts data from each pumping test separately to obtain optimal local estimates of hydraulic parameters, which are consequently fused using the generalized Millman formula, an algorithm for merging multiple correlated or uncorrelated local estimates. For both data fusion schemes, the basic inversion processor employed is the ensemble Kalman filter, which is employed to assimilate the temporal moments of impulse response functions obtained from the transient hydraulic head measurements resulting from multiple pumping tests. Assimilating the temporal moments instead of the hydraulic head transient data themselves is shown to provide a significant improvement in computational efficiency. Additionally, different assimilation strategies to improve the estimation of Ss are investigated. Results show that estimation of the K and Ss distributions using temporal moment analysis is fairly good, and the centralized inversion scheme consistently outperforms the decentralized inversion scheme

Assimilation of Historical Head Data to Estimate Spatial Distributions of Stream Bed and Aquifer Hydraulic Conductivity Fields

Management of water resources in alluvial aquifers relies mainly on understanding interactions between hydraulically connected streams and aquifers. Numerical models that simulate this interaction often are used as decision support tools in water resource management. However, the accuracy of numerical predictions relies heavily on the unknown system parameters (i.e. stream bed conductivity and aquifer hydraulic conductivity) which are spatially heterogeneous and difficult to measure directly. This paper employs an Ensemble Smoother to invert groundwater level measurements to jointly estimate spatially-varying streambed and alluvial aquifer hydraulic conductivity along a 35.6 km segment of the South Platte River in northeastern Colorado. The accuracy of the inversion procedure is evaluated using a synthetic experiment and historical groundwater level measurements, with the latter constituting the novelty of this study in the inversion and validation of high resolution fields of streambed and aquifer conductivities. Results show that the estimated streambed conductivity field and aquifer conductivity field produce an acceptable agreement between observed and simulated groundwater levels and stream flow rates. The estimated parameter fields are also used to simulate the spatially varying flow exchange between the alluvial aquifer and the stream, which exhibit high spatial variability along the river reach with a maximum average monthly aquifer gain of about 2.3 m3/day and a maximum average monthly aquifer loss of 2.8 m3/day, per unit area of streambed (m2). These results demonstrate that data assimilation inversion provides a reliable and computationally affordable tool to estimate the spatial variability of streambed and aquifer conductivities at high resolution in real-world systems

Hybrid Simulation for Construction Operations

Developing realistic and unbiased simulation models for construction operations require addressing the operational and strategic decision making levels. The dynamics and feedback processes observed in construction systems are responsible for the real behavior of such systems and drive the needs for hybrid and integrated simulation tools. The dominant simulation methods such as discrete event simulation (DES) and system dynamics (SD) are limited individually of capturing all the significant construction operation aspects that are responsible for generating the behaviour of realistic models. Therefore, this thesis presents a hybrid simulation method for simulating construction operations by utilizing the joint powerful features of the DES and SD methods. The proposed method provides a framework to integrate DES and SD on single computational platform. Developing a hybrid simulation model commences by decomposing the construction project into units, form which simulation models (e.g. DES or SD) are developed. A unidirectional variables interaction from DES to SD models is used. The interfacing process among simulation models is achieved by defining three variables: sender, interface, and receiver. The mechanism that controls data mapping processes between variables is outlined in a new developed synchronization method. The variables interaction protocol is described using formalism. Finally, a Hybrid Simulation Application (HiSim) is coded in VB.NET to demonstrate a sequential implementation of the developed method. A real-world earthmoving project is modeled and simulated to test the developed hybrid simulation method. The hybrid simulation structure uses unidirectional and sequential interactions between the components of DES and SD models. The simulation is run under three scenarios, is able to predict the real project completion duration with 92% accuracy, and captures the influences of the context level variables. The findings are expected to enhance hybrid simulation applications in construction and to allow for better understanding of the impact of various internal and external factors on the project schedule and its productivity performance

Editorial : automation and artificial intelligence in construction and management of civil infrastructure

The construction industry, similar to other industries, has been moving toward automation and implementation of AI tools to enhance analysis, management and decision-making. The construction industry typically takes longer than other industries in inaugurating innovation and advanced technologies due to the complex nature of the industry. Research effort is deemed necessary to understand needs and overcome challenges in terms of studying the capabilities and potential of existing tools and technologies in areas related to construction engineering and management. The current Research Topic attempted to collect relevant research work in terms of automation and AI application in constructing new assets and managing existing infrastructure. Further research is needed to standardize these processes and align research work with current needs

Stochastic analysis of flow and salt transport modeling in irrigation-drainage systems

2012 Spring.Includes bibliographical references.Sustainability of crop production in the Lower Arkansas River Basin in Colorado is seriously threatened by the continuous degradation of irrigated lands by the dual impact of soil salinization and waterlogging problems. Integration of improved irrigation practices, upgrades to the irrigation systems, and subsurface drainage are essential components of any plan to stop the deterioration of irrigated lands. Numerical simulations of irrigation and drainage systems are necessary to justify the consequent management actions. Despite the uncertainty of their predictions, numerical models are still indispensable decision support tools to investigate the feasibility of irrigation and drainage systems management plans. However, the uncertainties in input parameters to these models create a risk of misleading numerical results. That is beside the fact that the numerical models themselves are conceptual simplifications of the complex reality. The overarching objective of this dissertation is to investigate the impact of parameters uncertainty on the response of simulated irrigation-drainage systems. In the first part of the research, a Global Sensitivity Analysis (GSA) is conducted using a one-dimensional variably saturated problem to prioritize parameters according to their importance with respect to predefined performance indices. A number of GSA methods are employed for this purpose, and their comparative performances are investigated. Results show that only five parameters out of 18 parameters are responsible for around 73% of crop yield uncertainty. The second part introduces a method to reduce the computational requirements of Monte Carlo Simulations. Numerical simulation of variably saturated three-dimensional fields is typically a computationally intensive process, let alone Monte Carlo Simulations of such problems. In order to reduce the number of model evaluations while producing acceptable estimates of the output statistical properties, Cluster Analysis (CA) is used to group the input parameter realizations, e.g. hydraulic conductivity. The potentials of this approach are investigated using different: 1) clustering schemes; 2) clustering configurations, and 3) subsampling schemes. . Results show that response of 400 realizations ensemble can be efficiently approximated using selected 50 realizations. The third part of the research investigates the impact of input parameter uncertainty on the response of irrigation-drainage systems, particularly on crop yield and root zone hydrosalinity. The three-dimensional soil parameters, i.e. hydraulic conductivity, porosity, the pore size distribution (van Genuchten β) parameter, the inverse of the air entry pressure (van Genuchten α) parameter, the residual moisture content parameter, and dispersivity; are treated as spatial random processes. A sequential multivariate Monte Carlo simulation approach is implemented to produce correlated input parameter realizations. Other uncertain parameters that are considered in the study are irrigation application variability, irrigation water salinity, irrigation uniformity, preferential flow fraction, drain conductance coefficient, and crop yield model parameters. Results show that as the crop sensitivity to salinity increases, the crop yield standard deviation increases. The fourth part of the research investigates an approach for optimal sampling of multivariate spatial parameters in order to reduce their uncertainty. The Ensemble Kalman Filter is used as instrumentation to integrate the sampling of the hydraulic conductivity and the water level for a two-dimensional steady state problem. The possibility of combining designs for efficient prediction and for efficient geostatistical parameter estimation is also investigated. Moreover, the effect of relative prices of sampled parameters is also investigated. A multi-objective genetic algorithm is employed to solve the formulated integer optimization problem. Results reveal that the multi-objective genetic algorithm constitutes a convenient framework to integrate designs that are efficient for prediction and for geostatistical parameter estimation

AGU hydrology days 2011

2011 annual AGU hydrology days was held at Colorado State University on March 21 - March 23, 2011.Includes bibliographical references.Spatial heterogeneity of soil properties and uncertainty in root uptake model parameters make the numerical prediction of crop yield prone to a high degree of uncertainty. In this study, the spatial soil parameters are treated as multivariate correlated regionalized random parameters. Sequential indicator simulation is used to generate three-dimensional dependant realizations for hydraulic conductivity, porosity, Van Genuchten parameters and dispersivity. Other semi empirical parameters that control crop water uptake and subsurface drainage conductance where also randomized. Four hundred realizations for each of the soil parameters were generated and processed in the variably saturated flow and transport model (CSUID) to obtain the spatial statistical moments of the relative crop yield, root zone salinity and salt leaching fraction. The statistical distributions of drainage flow and salinity hydrographs were also calculated. Results show that parameter uncertainty significantly affects in-field relative crop yield variability and drainage flow and salinity effluent

تطوير الموارد البشرية في قطاع الانشاءات في قطاع غزة

The development of human resources in construction industry has become a necessity over the last few decades; the un-development of human resources is a major factor inhibiting effective planning and implementation of construction projects in Gaza Strip. The employment of craftsmen in construction is characterized by unsuitability; the construction worker is hired on a project with the objectives of working him out of job by completing the project. The construction industry faces many challenges. Many of these challenges arise from the need to keep a skilled and competitive craft workforce, challenges such as changing demographic characteristics, changes in the economics and technology, difficulties in maintaining a skilled work force, rapid changes in the economy, social changes and organization technological environment changes. The main objective of this study is to study the causes of construction workers dissatisfaction in the construction sectors, identification of the factors that affect the development of the human resources in the Gaza Strip construction industry and development of a model for the human resources development in construction sector. The results point to that the main causes of construction workers dissatisfaction are: lack of possibilities for better future in the construction sector, lack of future skills improvement and training by the employer, lack of job security, lack of necessary incentives, working hours per day exceeding 8 hours and delay in salary payment The results indicated show that the main factors for human resources development in the construction industry are: skills development of manpower to increase performance, availability of appropriate training programs that can be implemented and measured, improve communication skills between project parties, political and security stability in the region for investment in construction and availability of training institutions to develop manpower skills. The finding of the study concluded the important of construction workforce characteristics, statistics and future trends. It also aims to the perceptions of the construction workers and employers. The findings of the study are of immense importance to policy makers in their mission to maintain skilled and adequate construction workforce able to face the future demand of this industry. The study recommends gathering statistical information on the construction workforce available in the construction sector, conducting training and education programs for the project mangers, site engineers and workforce to improve their skills. In addition to this a conceptual model for the development of the human resources in the construction industry in Gaza Strip was designed

O processo de produção do conhecimento nos PPGs de teologia

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências da Educação. Programa de Pós-Graduação em Educação.Nesta tese, o objetivo foi investigar as induções geradas pelo sistema de avaliação e fomento da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes) nos processos de produção de conhecimento dos Programas de Pós-graduação em Teologia (PPGTs). Problematizou-se a influência dos critérios de avaliação da Capes nos processos de produção do conhecimento no campo epistemológico da Teologia, tendo como aporte teórico o conceito de #campo# de Bourdieu. Para análise, foi realizado estudo de caso múltiplo em três Programas de Pós-graduação em Teologia com conceitos iguais ou superiores a cinco e que ofereciam cursos de mestrado e doutorado reconhecidos pelas suas igrejas # católica ou protestante #, em período anterior à inserção no sistema Capes. A metodologia envolveu entrevistas e coleta de dados em documentos disponibilizados pela Capes e pelos PPGTs. As entrevistas foram realizadas com dois grupos: dez pesquisadores da área da Teologia não vinculados aos PPGT em análise, com o objetivo de obter umolhar privilegiado sobre o campo de conhecimento teológico, e um segundo, composto por doze professores, quatro de cada PPGT em análise, sendo o critério de escolha: o tempo de vinculação ao PPGT; ter atuação antes e depois da inserção na Capes. A coleta de dados teve como base os documentos: fichas de avaliação dos PPGTs emitidas pela Capes; proposta dos PPGT em análise; produção docente e discente veiculada nos currículos lattes; análise das publicações nas revistas científicas dos PPGT pesquisados. Os resultados da pesquisa apontam que a inserção no Sistema de avaliação e fomento exigiu dos PPGTs mudanças, estruturais e epistemológicas, tais como: alterações nas linhas de pesquisa, nas teses e dissertações, bem como transformações nos tempos e meios de veiculação da produção docente. Foi constatado como um paradigma avaliativo pode afetar um determinado campo de conhecimento, causando uma inflexão epistemológica, principalmente quando os PPGTs buscam alcançar o topo do ranking do Sistema Capes. Há uma zona de tensão entre a produção do conhecimento religioso e as determinações indutoras do organismo de avaliação, regulação e financiamento da pós-graduação no Brasil. Há evidências de uma reconstrução e reconfiguração do campo de produção do conhecimento teológico nos Programas de Pósgraduação em Teologia analisados na busca de adaptação aos critérios de avaliação da Capes. Os entrevistados apontaram e analisaram os ganhos, perdas e embates decorrentes desse processoThe purpose of this thesis was to investigate the changes generated by the evaluation and finance system of the Coordination for Personnel Improvement in Higher Education (CAPES) in the processes of production of knowledge of graduate theology programs (PPGTs). It analyzed the influence of CAPES# evaluation criteria on the processes of knowledge production in the epistemological field of Theology. The theoretical support for the study was Bourdieu#s concept of #field.# A multiple case study was conducted at three graduate theology programs that received grades equal or higher than 5 and that offered masters and doctoral courses recognized by their churches # Catholic or Protestant # in a period previous to their insertion in the CAPES system. The methodology involved interviews and data collection from documents provided by Capes and by the graduate programs. The interviews were conducted with two groups. The first included 10 researchers from the field of Theology not linked to the graduate programs being studied, to obtain a good look at the theological field of knowledge. The second group was composed of 12 professors, four from each graduate program being analyzed. The criteria used to select the professors was the time of their relationship with the program and whether they had worked before and after the program#s insertion in the Capes system. The data collection was based on documents, including evaluation records of the graduate programs issued by Capes; the course proposal of the program being studied; the production of students and professors as indicated in the CAPES on-line data base (lattes); and an analysis of publications in scientific journals by the graduate programs being studied. The results of the research indicate that the insertion in the evaluation and financial support system required that the graduate programs make both structural and epistemological changes. These changes included: alterations in the research lines, in the theses and the dissertations, as well as transformations in the frequency and means of presentation of the work of the professors. It was found how an evaluative paradigm could affect a given field of knowledge, causing an epistemological inflection, mainly, when the graduate programs sought to reach the top of the Capes System ranking. There is a zone of tension between the production of religious knowledge and the inductive determinations of the agency responsible for evaluation, regulation and finance of graduate programs in Brazil. There is evidence of a reconstruction and reconfiguration of the field of production of theological knowledge in the graduate theology programs analyzed, as they sought to adapt to Capes# evaluation criteria. The people interviewed indicated and analyzed the gains, losses and conflicts related to this proces

Modeling spatial and temporal variability

Presented at the fifth international conference on irrigation and drainage, Irrigation and drainage for food, energy and the environment on November 3-6, 2009 in Salt Lake City, Utah.Includes bibliographical references.The Colorado State University irrigation and drainage model (CSUID) is a three dimensional variable saturated-unsaturated numerical model that simulates the subsurface flow and transport processes. A wide range of enhancements have been done to CSUID to fully simulate the response of agricultural fields to external stresses such as subsurface drainage systems, root extractions and irrigation activities. The model is also capable of simulating salinity transport process through the vadose zone and in the saturated zone. The partition of salinity between the soil solid phase and the water phase is included in the model to simulate the accumulation of salts in the root zone. The strength of CSUID is in its ability to simulate irrigation-drainage activities taking into account spatially and temporal variably in water quality and quantity and under spatial heterogeneous soil properties. Soil properties such as hydraulic conductivity, porosity, Van Genutchen retention curve parameters, storativity, dispersivity, partition coefficients are all modeled as spatially variables. Having a model with these capabilities is an important step toward understanding the uncertainty in the design and management of irrigation-drainage systems. The model contains a Graphical User Interface that allows the user to visualize the input and output