Kurt Larson - Academia.edu (original) (raw)

Papers by Kurt Larson

Research paper thumbnail of Integrated modeling and experimental programs to predict brine and gas flow at the Waste Isolation Pilot Plant

Evaluation of the performance of the WIPP repository involves modeling of brine and gas flow in t... more Evaluation of the performance of the WIPP repository involves modeling of brine and gas flow in the host rocks of the Salado Formation, which consist of halite and higher permeability anhydrite interbeds. Numerous physical, chemical, and structural processes, some of them coupled, must be understood to perform this modeling. Gas generation within the repository, for example, is strongly coupled to the amount of brine inflow to the repository because brine aids in the corrosion of metals and associated generation of hydrogen gas. Increasing gas pressure in the repository, in turn, decreases the rate of brine inflow. Ultimately, the gas pressure may exceed the brine pressure and gas may flow out of the repository. The initial models used by WIPP Performance Assessment (PA) were simplified because of a lack of WlPP-specific data on important processes and parameters. Relative-permeability curves and a correlation between threshold pressure and permeability taken from studies reported in the literature were used in PA models prior to being experimentally verified as appropriate for WIPP. In addition, interbed permeabilities were treated as constant and independent of effective stress in early models. Subsequently, the process of interbed fracturing (or fracture dilation) was recognized to limit gas pressures in the repository to values below lithostatic, and assumed (and unverified) relationships between porosity, permeability, and pore pressure were employed. Parametersensitivity studies performed using the simplified models identified important parameters for which sitespecific data were needed. Unrealistic modeling results, such as room pressures substantially above lithostatic, showed the need to include additional processes in the models. Field and laboratory experimental programs have been initiated in conjunction with continued model development to provide information on important processes and parameters. Current field experiments are aimed at determining the permeability of anhydrite and halite beds under undisturbed conditions, the pressuredependence of anhydrite fracture permeability, and the threshold pressure of anhydrite fractures. Laboratory experiments are being performed on anhydrite core samples to determine capillary-pressure curves, relative-permeability curves, and permeability and porosity as a function of applied stress. The current PA models built upon these experimental data are considerably more realistic and credible than the initial models used and, in some cases, predict significantly different consequences.

Research paper thumbnail of Certifying the Waste Isolation Pilot Plant: Lessons Learned from the WIPP Experience

The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.

Research paper thumbnail of SANDIA REPORT The Effect of Stratigraphic Dip on Brine Inflow and Gas Migration at the Waste Isolation Pilot Plant

The natural dip of the Salado Formation at the Waste Isolation Pilot Plant (WIPP), although regio... more The natural dip of the Salado Formation at the Waste Isolation Pilot Plant (WIPP), although regionally only about 1°, has the potential to affect brine inflow and gas-migration distances due to buoyancy forces. Current models, including those in WIPP Performance Assessment calculations, assume a perfectly horizontal repository and stratigraphy. With the addition of buoyancy forces due to the dip, brine and gas flow patterns can be affected. Brine inflow may increase due to countercurrent flow, and gas may preferentially migrate up dip. This scoping study has used analytical and numerical modeling to evaluate the impact of the dip on brine inflow and gas-migration distances at the WIPP in one, two, and three dimensions. Sensitivities to interbed permeabilities, two-phase curves, gas-generation rates, and interbed fracturing were studied.

Research paper thumbnail of The effect of stratigraphic dip on multiphase flow at the Waste Isolation Pilot Plant

Research paper thumbnail of Lessons Learned from WIPP Site Characteriztion, Performance Assessment, and Regulatory Review Related to Radionuclide Migration through Water-Conducting Features

Research paper thumbnail of Using a multiphase flow code to model the coupled effects of repository consolidation and multiphase brine and gas flow at the Waste Isolation Pilot Plant

The Waste Isolation Pilot Plant (WIPP) is a U.S. Department of Energy facility designed to demons... more The Waste Isolation Pilot Plant (WIPP) is a U.S. Department of Energy facility designed to demonstrate the safe underground disposal of transuranic waste. The WIPP repository lies within the Salado Formation, a thick sequence of bedded pure and impure halite with thin, laterally continuous interbeds of anhydrite. The underground waste storage area is designed to have eight waste disposal panels, each of which will contain seven waste disposal rooms. Each disposal room, approximately 4 m high, 10 m wide, and 91 m long, is to be filled with steel drums containing contact-handled (CH) transuranic (TRU) waste. Following waste emplacement, each room will be backfilled with crushed salt. Due to deviatoric stress introduced by excavation, the walls of the waste disposal rooms in the repository will deform over time, consolidating waste containers and salt backfill, thereby decreasing the void volume of the repository.

Research paper thumbnail of A summary of methods for approximating salt creep and disposal room closure in numerical models of multiphase flow

Research paper thumbnail of Coupled multiphase flow and closure analysis of repository response to waste-generated gas at the Waste Isolation Pilot Plant (WIPP)

A long-term assessment of the Waste Isolation Pilot Plant (WIPP) repository performance must cons... more A long-term assessment of the Waste Isolation Pilot Plant (WIPP) repository performance must consider the impact of gas generation resulting from the corrosion and microbial degradation of the emplaced waste. A multiphase fluid flow code, TOUGH2/EOS8, was adapted to model the processes of gas generation, disposal room creep closure, and multiphase (brine and gas) fluid flow, as well as the

Research paper thumbnail of Summary of applications of TOUGH2 to the evaluation of multiphase flow processes at the WIPP

Research paper thumbnail of Modification of the ART1 architecture based on category theoretic design principles

International Symposium on Neural Networks, 2005

Many studies have addressed the knowledge representation capability of neural networks. A recentl... more Many studies have addressed the knowledge representation capability of neural networks. A recently-developed mathematical semantic theory explains the relationship between knowledge and its representation in connectionist systems. The theory yields design principles for neural networks whose behavioral repertoire expresses any desired capability that can be expressed logically. In this paper, we show how the design principle of limit formation can

Research paper thumbnail of Implementing wide baseline matching algorithms on a graphics processing unit

Wide baseline matching is the state of the art for object recognition and image registration prob... more Wide baseline matching is the state of the art for object recognition and image registration problems in computer vision. Though effective, the computational expense of these algorithms limits their application to many real-world problems. The performance of wide baseline matching algorithms may be improved by using a graphical processing unit as a fast multithreaded co-processor. In this paper, we present

Research paper thumbnail of Sparse imaging for fast electron microscopy

Computational Imaging XI, 2013

ABSTRACT

Research paper thumbnail of Applying category theory to improve the performance of a neural architecture

Neurocomputing, 2009

A recently-developed mathematical semantic theory explains the relationship between knowledge and... more A recently-developed mathematical semantic theory explains the relationship between knowledge and its representation in connectionist systems. The semantic theory is based upon category theory, the mathematical theory of structure. A product of its explanatory capability is a set of principles to guide the design of future neural architectures and enhancements to existing designs. We claim that this mathematical semantic approach to network design is an effective basis for advancing the state of the art. We offer two experiments to support this claim. One of these involves multispectral imaging using data from a satellite camera. 2 weights? How do we understand connectionist learning, generalization, and specialization in terms of data and prior knowledge? A systematic means of addressing these questions can serve as a fundamental and comprehensive base for analysis and design provided that the understanding is accompanied by mathematical rigor. But this begs the question of whether there is a form of mathematics that can serve as a vehicle for addressing questions about neural network semantics. We introduce a form of mathematics that serves as such a vehicle along with an experiment testing this claim.

Research paper thumbnail of Certifying the Waste Isolation Pilot Plant: Lessons Learned from the WIPP Experience

The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.

Research paper thumbnail of Midterm Report–Promotes Using Wireless Sensor Networks for Low-Cost Fast-Installation Three-Dimensional Environment Modelling

pi.unl.edu

I. INTRODUCTION A three dimensional model of an environment can be constructed using several imag... more I. INTRODUCTION A three dimensional model of an environment can be constructed using several images of the same scene at different camera angles. This technique has a wide variety of applica-tions, including robotics, motion capture, and security systems. This approach ...

Research paper thumbnail of Scene kinetics mitigation using factor analysis with derivative factors

Proceedings of Spie the International Society For Optical Engineering, Aug 1, 2010

Line of sight jitter in staring sensor data combined with scene information can obscure critical ... more Line of sight jitter in staring sensor data combined with scene information can obscure critical information for change analysis or target detection. Consequently before the data analysis, the jitter effects must be significantly reduced. Conventional principal component analysis (PCA) has been used to obtain basis vectors for background estimation; however PCA requires image frames that contain the jitter variation that is to be modeled. Since jitter is usually chaotic and asymmetric, a data set containing all the variation without the changes to be detected is typically not available. An alternative approach, Scene Kinetics Mitigation, first obtains an image of the scene. Then it computes derivatives of that image in the horizontal and vertical directions. The basis set for estimation of the background and the jitter consists of the image and its derivative factors. This approach has several advantages including: 1) only a small number of images are required to develop the model, 2) the model can estimate backgrounds with jitter different from the input training images, 3) the method is particularly effective for sub-pixel jitter, and 4) the model can be developed from images before the change detection process. In addition the scores from projecting the factors on the background provide estimates of the jitter magnitude and direction for registration of the images. In this paper we will present a discussion of the theoretical basis for this technique, provide examples of its application, and discuss its limitations.

Research paper thumbnail of Integrated modeling and experimental programs to predict brine and gas flow at the Waste Isolation Pilot Plant

Evaluation of the performance of the WIPP repository involves modeling of brine and gas flow in t... more Evaluation of the performance of the WIPP repository involves modeling of brine and gas flow in the host rocks of the Salado Formation, which consist of halite and higher permeability anhydrite interbeds. Numerous physical, chemical, and structural processes, some of them coupled, must be understood to perform this modeling. Gas generation within the repository, for example, is strongly coupled to the amount of brine inflow to the repository because brine aids in the corrosion of metals and associated generation of hydrogen gas. Increasing gas pressure in the repository, in turn, decreases the rate of brine inflow. Ultimately, the gas pressure may exceed the brine pressure and gas may flow out of the repository. The initial models used by WIPP Performance Assessment (PA) were simplified because of a lack of WlPP-specific data on important processes and parameters. Relative-permeability curves and a correlation between threshold pressure and permeability taken from studies reported in the literature were used in PA models prior to being experimentally verified as appropriate for WIPP. In addition, interbed permeabilities were treated as constant and independent of effective stress in early models. Subsequently, the process of interbed fracturing (or fracture dilation) was recognized to limit gas pressures in the repository to values below lithostatic, and assumed (and unverified) relationships between porosity, permeability, and pore pressure were employed. Parametersensitivity studies performed using the simplified models identified important parameters for which sitespecific data were needed. Unrealistic modeling results, such as room pressures substantially above lithostatic, showed the need to include additional processes in the models. Field and laboratory experimental programs have been initiated in conjunction with continued model development to provide information on important processes and parameters. Current field experiments are aimed at determining the permeability of anhydrite and halite beds under undisturbed conditions, the pressuredependence of anhydrite fracture permeability, and the threshold pressure of anhydrite fractures. Laboratory experiments are being performed on anhydrite core samples to determine capillary-pressure curves, relative-permeability curves, and permeability and porosity as a function of applied stress. The current PA models built upon these experimental data are considerably more realistic and credible than the initial models used and, in some cases, predict significantly different consequences.

Research paper thumbnail of Certifying the Waste Isolation Pilot Plant: Lessons Learned from the WIPP Experience

The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.

Research paper thumbnail of SANDIA REPORT The Effect of Stratigraphic Dip on Brine Inflow and Gas Migration at the Waste Isolation Pilot Plant

The natural dip of the Salado Formation at the Waste Isolation Pilot Plant (WIPP), although regio... more The natural dip of the Salado Formation at the Waste Isolation Pilot Plant (WIPP), although regionally only about 1°, has the potential to affect brine inflow and gas-migration distances due to buoyancy forces. Current models, including those in WIPP Performance Assessment calculations, assume a perfectly horizontal repository and stratigraphy. With the addition of buoyancy forces due to the dip, brine and gas flow patterns can be affected. Brine inflow may increase due to countercurrent flow, and gas may preferentially migrate up dip. This scoping study has used analytical and numerical modeling to evaluate the impact of the dip on brine inflow and gas-migration distances at the WIPP in one, two, and three dimensions. Sensitivities to interbed permeabilities, two-phase curves, gas-generation rates, and interbed fracturing were studied.

Research paper thumbnail of The effect of stratigraphic dip on multiphase flow at the Waste Isolation Pilot Plant

Research paper thumbnail of Lessons Learned from WIPP Site Characteriztion, Performance Assessment, and Regulatory Review Related to Radionuclide Migration through Water-Conducting Features

Research paper thumbnail of Using a multiphase flow code to model the coupled effects of repository consolidation and multiphase brine and gas flow at the Waste Isolation Pilot Plant

The Waste Isolation Pilot Plant (WIPP) is a U.S. Department of Energy facility designed to demons... more The Waste Isolation Pilot Plant (WIPP) is a U.S. Department of Energy facility designed to demonstrate the safe underground disposal of transuranic waste. The WIPP repository lies within the Salado Formation, a thick sequence of bedded pure and impure halite with thin, laterally continuous interbeds of anhydrite. The underground waste storage area is designed to have eight waste disposal panels, each of which will contain seven waste disposal rooms. Each disposal room, approximately 4 m high, 10 m wide, and 91 m long, is to be filled with steel drums containing contact-handled (CH) transuranic (TRU) waste. Following waste emplacement, each room will be backfilled with crushed salt. Due to deviatoric stress introduced by excavation, the walls of the waste disposal rooms in the repository will deform over time, consolidating waste containers and salt backfill, thereby decreasing the void volume of the repository.

Research paper thumbnail of A summary of methods for approximating salt creep and disposal room closure in numerical models of multiphase flow

Research paper thumbnail of Coupled multiphase flow and closure analysis of repository response to waste-generated gas at the Waste Isolation Pilot Plant (WIPP)

A long-term assessment of the Waste Isolation Pilot Plant (WIPP) repository performance must cons... more A long-term assessment of the Waste Isolation Pilot Plant (WIPP) repository performance must consider the impact of gas generation resulting from the corrosion and microbial degradation of the emplaced waste. A multiphase fluid flow code, TOUGH2/EOS8, was adapted to model the processes of gas generation, disposal room creep closure, and multiphase (brine and gas) fluid flow, as well as the

Research paper thumbnail of Summary of applications of TOUGH2 to the evaluation of multiphase flow processes at the WIPP

Research paper thumbnail of Modification of the ART1 architecture based on category theoretic design principles

International Symposium on Neural Networks, 2005

Many studies have addressed the knowledge representation capability of neural networks. A recentl... more Many studies have addressed the knowledge representation capability of neural networks. A recently-developed mathematical semantic theory explains the relationship between knowledge and its representation in connectionist systems. The theory yields design principles for neural networks whose behavioral repertoire expresses any desired capability that can be expressed logically. In this paper, we show how the design principle of limit formation can

Research paper thumbnail of Implementing wide baseline matching algorithms on a graphics processing unit

Wide baseline matching is the state of the art for object recognition and image registration prob... more Wide baseline matching is the state of the art for object recognition and image registration problems in computer vision. Though effective, the computational expense of these algorithms limits their application to many real-world problems. The performance of wide baseline matching algorithms may be improved by using a graphical processing unit as a fast multithreaded co-processor. In this paper, we present

Research paper thumbnail of Sparse imaging for fast electron microscopy

Computational Imaging XI, 2013

ABSTRACT

Research paper thumbnail of Applying category theory to improve the performance of a neural architecture

Neurocomputing, 2009

A recently-developed mathematical semantic theory explains the relationship between knowledge and... more A recently-developed mathematical semantic theory explains the relationship between knowledge and its representation in connectionist systems. The semantic theory is based upon category theory, the mathematical theory of structure. A product of its explanatory capability is a set of principles to guide the design of future neural architectures and enhancements to existing designs. We claim that this mathematical semantic approach to network design is an effective basis for advancing the state of the art. We offer two experiments to support this claim. One of these involves multispectral imaging using data from a satellite camera. 2 weights? How do we understand connectionist learning, generalization, and specialization in terms of data and prior knowledge? A systematic means of addressing these questions can serve as a fundamental and comprehensive base for analysis and design provided that the understanding is accompanied by mathematical rigor. But this begs the question of whether there is a form of mathematics that can serve as a vehicle for addressing questions about neural network semantics. We introduce a form of mathematics that serves as such a vehicle along with an experiment testing this claim.

Research paper thumbnail of Certifying the Waste Isolation Pilot Plant: Lessons Learned from the WIPP Experience

The Energy Citations Database (ECD) provides access to historical and current research (1948 to t... more The Energy Citations Database (ECD) provides access to historical and current research (1948 to the present) from the Department of Energy (DOE) and predecessor agencies.

Research paper thumbnail of Midterm Report–Promotes Using Wireless Sensor Networks for Low-Cost Fast-Installation Three-Dimensional Environment Modelling

pi.unl.edu

I. INTRODUCTION A three dimensional model of an environment can be constructed using several imag... more I. INTRODUCTION A three dimensional model of an environment can be constructed using several images of the same scene at different camera angles. This technique has a wide variety of applica-tions, including robotics, motion capture, and security systems. This approach ...

Research paper thumbnail of Scene kinetics mitigation using factor analysis with derivative factors

Proceedings of Spie the International Society For Optical Engineering, Aug 1, 2010

Line of sight jitter in staring sensor data combined with scene information can obscure critical ... more Line of sight jitter in staring sensor data combined with scene information can obscure critical information for change analysis or target detection. Consequently before the data analysis, the jitter effects must be significantly reduced. Conventional principal component analysis (PCA) has been used to obtain basis vectors for background estimation; however PCA requires image frames that contain the jitter variation that is to be modeled. Since jitter is usually chaotic and asymmetric, a data set containing all the variation without the changes to be detected is typically not available. An alternative approach, Scene Kinetics Mitigation, first obtains an image of the scene. Then it computes derivatives of that image in the horizontal and vertical directions. The basis set for estimation of the background and the jitter consists of the image and its derivative factors. This approach has several advantages including: 1) only a small number of images are required to develop the model, 2) the model can estimate backgrounds with jitter different from the input training images, 3) the method is particularly effective for sub-pixel jitter, and 4) the model can be developed from images before the change detection process. In addition the scores from projecting the factors on the background provide estimates of the jitter magnitude and direction for registration of the images. In this paper we will present a discussion of the theoretical basis for this technique, provide examples of its application, and discuss its limitations.