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Full-Text Articles in Remote Sensing

Sparse Coding Based Feature Representation Method For Remote Sensing Images, Ender Oguslu Apr 2016

Sparse Coding Based Feature Representation Method For Remote Sensing Images, Ender Oguslu

Electrical & Computer Engineering Theses & Dissertations

In this dissertation, we study sparse coding based feature representation method for the classification of multispectral and hyperspectral images (HSI). The existing feature representation systems based on the sparse signal model are computationally expensive, requiring to solve a convex optimization problem to learn a dictionary. A sparse coding feature representation framework for the classification of HSI is presented that alleviates the complexity of sparse coding through sub-band construction, dictionary learning, and encoding steps. In the framework, we construct the dictionary based upon the extracted sub-bands from the spectral representation of a pixel. In the encoding step, we utilize a soft …


Sparse Coding Based Dense Feature Representation Model For Hyperspectral Image Classification, Ender Oguslu, Guoqing Zhou, Zezhong Zheng, Khan Iftekharuddin, Jiang Li Jan 2015

Sparse Coding Based Dense Feature Representation Model For Hyperspectral Image Classification, Ender Oguslu, Guoqing Zhou, Zezhong Zheng, Khan Iftekharuddin, Jiang Li

Electrical & Computer Engineering Faculty Publications

We present a sparse coding based dense feature representation model (a preliminary version of the paper was presented at the SPIE Remote Sensing Conference, Dresden, Germany, 2013) for hyperspectral image (HSI) classification. The proposed method learns a new representation for each pixel in HSI through the following four steps: sub-band construction, dictionary learning, encoding, and feature selection. The new representation usually has a very high dimensionality requiring a large amount of computational resources. We applied the l1/lq regularized multiclass logistic regression technique to reduce the size of the new representation. We integrated the method with a linear …


Hyperspectral Image Classification Using A Spectral-Spatial Sparse Coding Model, Ender Oguslu, Guoqing Zhou, Jiang Li, Lorenzo Bruzzone (Ed.) Jan 2013

Hyperspectral Image Classification Using A Spectral-Spatial Sparse Coding Model, Ender Oguslu, Guoqing Zhou, Jiang Li, Lorenzo Bruzzone (Ed.)

Electrical & Computer Engineering Faculty Publications

We present a sparse coding based spectral-spatial classification model for hyperspectral image (HSI) datasets. The proposed method consists of an efficient sparse coding method in which the l1/lq regularized multi-class logistic regression technique was utilized to achieve a compact representation of hyperspectral image pixels for land cover classification. We applied the proposed algorithm to a HSI dataset collected at the Kennedy Space Center and compared our algorithm to a recently proposed method, Gaussian process maximum likelihood (GP-ML) classifier. Experimental results show that the proposed method can achieve significantly better performances than the GP-ML classifier when training data …


First Remote Sensing Observations Of Trifluoromethane (Hfc-23) In The Upper Troposphere And Lower Stratosphere, Jeremy J. Harrison, Christopher D. Boone, Alexander T. Brown, Nicholas D. C. Allen, Geoffrey C. Toon, Peter F. Bernath Jan 2012

First Remote Sensing Observations Of Trifluoromethane (Hfc-23) In The Upper Troposphere And Lower Stratosphere, Jeremy J. Harrison, Christopher D. Boone, Alexander T. Brown, Nicholas D. C. Allen, Geoffrey C. Toon, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

This work reports the first remote sensing measurements of atmospheric HFC-23 (CHF3) using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) and the Jet Propulsion Laboratory Mark IV (MkIV) balloon interferometer. A total of 8809 ACE occultations measured between 2004 and 2010 have been processed, along with 24 MkIV occultations measured between 1989 and 2007. ACE data (yearly averages over the 10-25 km altitude range) in the tropics/subtropics (40°S-40°N) reveal a trend of 4.0 ± 1.6% per year in the growth of HFC-23 for 2004-2009 (or 3.9 ± 1.2% per year for 2004-2010), …


Sparse Coding For Hyperspectral Images Using Random Dictionary And Soft Thresholding, Ender Oguslu, Khan Iftekharuddin, Jiang Li, Mark Allen Neifeld (Ed.), Amit Ashok (Ed.) Jan 2012

Sparse Coding For Hyperspectral Images Using Random Dictionary And Soft Thresholding, Ender Oguslu, Khan Iftekharuddin, Jiang Li, Mark Allen Neifeld (Ed.), Amit Ashok (Ed.)

Electrical & Computer Engineering Faculty Publications

Many techniques have been recently developed for classification of hyperspectral images (HSI) including support vector machines (SVMs), neural networks and graph-based methods. To achieve good performances for the classification, a good feature representation of the HSI is essential. A great deal of feature extraction algorithms have been developed such as principal component analysis (PCA) and independent component analysis (ICA). Sparse coding has recently shown state-of-the-art performances in many applications including image classification. In this paper, we present a feature extraction method for HSI data motivated by a recently developed sparse coding based image representation technique. Sparse coding consists of a …


Design And Demonstration Of A Miniature Lidar System For Rover Applications, Benjamin Robinson Apr 2011

Design And Demonstration Of A Miniature Lidar System For Rover Applications, Benjamin Robinson

Electrical & Computer Engineering Theses & Dissertations

Public awareness of harmful human environmental effects such as global warming has increased greatly in recent years and researchers have increased their efforts in gaining more knowledge about the Earth's atmosphere. Natural and man-made processes pose threats lo the environment and human life, so knowledge of all atmospheric processes is necessary. Ozone and aerosols are important factors in many atmospheric processes and active remote sensing techniques provide a way lo analyze their quantity and distribution.

A compact ground-based lidar system for a robotic platform meant for atmospheric aerosol measurements was designed, tested, and evaluated. The system will eventually be deployed …


A Differential Absorption Model For Remote Sensing Of Atmospheric Pressure, Shivam J. Shah Jul 2010

A Differential Absorption Model For Remote Sensing Of Atmospheric Pressure, Shivam J. Shah

Electrical & Computer Engineering Theses & Dissertations

The goal of the project is to develop and test a "model based" radar processing strategy that is compatible with the concept of a "cognitive radar". The basic approach will be to develop a cognitive radar algorithm (genetic algorithm) based on the capabilities of an existing commercially available Software Radio. While the focus of this effort is the development of a candidate approach for genetic algorithm, the longer term goal would be to implement the approach using this software radio technology to provide a low cost radar processor. The proposed technology would use differential absorption radar working at the 50-56 …


A Compact Lidar For Aircraft Ozone Atmospheric Measurements, Joel A. Marcia Apr 2009

A Compact Lidar For Aircraft Ozone Atmospheric Measurements, Joel A. Marcia

Electrical & Computer Engineering Theses & Dissertations

Researchers and the general public have expressed great concern over how human activities exacerbate pollution's deteriorating impact upon the environment. Effects such as global warming, air quality and ozone layer depletion are but a few examples that can have a dramatic effect on the quality of life worldwide.

A compact lidar system for the purpose of aircraft ozone atmospheric measurements was tested and evaluated. This system will eventually be deployed for aircraft-based, and possibly unpiloted atmospheric vehicle (UAV), ozone and aerosol measurements to improve our understanding of ozone production and transport. Each of the major subsystems was characterized and from …


A Bio-Optical Model For Syringodium Filiforme Canopies, Margaret A. Stoughton Apr 2009

A Bio-Optical Model For Syringodium Filiforme Canopies, Margaret A. Stoughton

OES Theses and Dissertations

Seagrasses are significant ecological and biogeochemical agents in shallow water ecosystems throughout the world. In many regions, seagrass meadows occupy a sufficient fraction of the coastal zone, and generate optical signatures that can be observed from space. Bio-optical models of light absorption and scattering by submerged plant canopies for certain species such as Thalassia testudinum and Zostera marina have successfully modeled the plane irradiance distribution and photosynthesis within the submerged canopies. Syringodium filiforme differs &om T. testudinttm and Z marina, in leaf morphology and canopy architecture. The objective of this study was to develop a radiative transfer model that …


Sensitive Detection Of Novel Effects And Characteristic Signal Structure Of Higher Harmonic Detection In Wavelength Modulation Spectroscopy, Mohammad Amir Khan Jan 2009

Sensitive Detection Of Novel Effects And Characteristic Signal Structure Of Higher Harmonic Detection In Wavelength Modulation Spectroscopy, Mohammad Amir Khan

Electrical & Computer Engineering Theses & Dissertations

We discuss experimental and theoretical results of absorption features of the oxygen A-band transitions when synchronous detection at higher harmonics using Wavelength Modulation Spectroscopy (WMS) is performed. A key aspect of structure higher harmonic detection is discussed. It is shown that the signal magnitude and spectral locations of turning points and zero crossings of WMS signal demonstrate key signatures of collision dynamics of gaseous specie parameters and lineshape parameters. In addition, it is also shown that these salient features provide sensitive probes for any changes in the gas environment or lineshape parameters. We discuss several advantages and subtle physical effects …


Geo-Rectification Of Aerial Images For Detecting Changes In Terrain, Diana Vincent Oct 2008

Geo-Rectification Of Aerial Images For Detecting Changes In Terrain, Diana Vincent

Electrical & Computer Engineering Theses & Dissertations

With increasing terrorist attacks around the world, detection of hidden bombs like IEDs (Improvised Explosive devices) has become very important. The main aim of this thesis is to develop an automatic change detection system to detect changes in terrain. It is mainly used in military applications for protection of military convoys. In order to detect the presence of IED's, an Unmanned Aerial Vehicle (UAV) is flown over a proposed convoy route to develop a baseline scene. Prior to the launch of the convoy the UA V is flown again over the same route to detect any significant scene changes that …


Aerial And Satellite Image Processing Applications, Srinivas K. Jakkula Oct 2008

Aerial And Satellite Image Processing Applications, Srinivas K. Jakkula

Electrical & Computer Engineering Theses & Dissertations

Aerial and satellite images are used extensively in many trip and mapping software packages, such as Google Earth etc. Aerial images differ significantly due to the variations in atmospheric clarity, atmospheric layer density, humidity, temperature, and season under which the aerial images are captured. Among the issues in effective utilization of aerial images, color tone discrepancy is the inconsistency in brightness, saturation, or color balance between images representing adjacent areas, causing adjacent areas appear significantly different that would otherwise be similar. Aenal images are also routinely used as ground textures to simulate Earth surface and 3D features on Earth in …


Seasonal Adaptation Of Vegetation Color In Satellite Images, Srinivas Jakkula, Vamsi K.R. Mantena, Ramu Pedada, Yuzhong Shen, Jiang Li, Hamid R. Arabnia (Ed.) Jan 2008

Seasonal Adaptation Of Vegetation Color In Satellite Images, Srinivas Jakkula, Vamsi K.R. Mantena, Ramu Pedada, Yuzhong Shen, Jiang Li, Hamid R. Arabnia (Ed.)

Electrical & Computer Engineering Faculty Publications

Remote sensing techniques like NDVI (Normal Difference vegetative Index) when applied to phenological variations in aerial images, ascertained the seasonal rise and decline of photosynthetic activity in different seasons, resulting in different color tones of vegetation. The rise and fall of NDVI values decide the biological response, either the green up or brown down [1]. Vegetation in green up period appears with more vegetative vigor and during brown down period it has a dry appearance. This paper proposes a novel method that identifies vegetative patterns in satellite images and then alters vegetation color to simulate seasonal changes based on training …


Vegetation Identification Based On Satellite Imagery, Vamsi K.R. Mantena, Ramu Pedada, Srinivas Jakkula, Yuzhong Shen, Jiang Li, Hamid R. Arabnia (Ed.) Jan 2008

Vegetation Identification Based On Satellite Imagery, Vamsi K.R. Mantena, Ramu Pedada, Srinivas Jakkula, Yuzhong Shen, Jiang Li, Hamid R. Arabnia (Ed.)

Electrical & Computer Engineering Faculty Publications

Automatic vegetation identification plays an important role in many applications including remote sensing and high performance flight simulations. This paper presents a method to automatically identify vegetation based upon satellite imagery. First, we utilize the ISODATA algorithm to cluster pixels in the images where the number of clusters is determined by the algorithm. We then apply morphological operations to the clustered images to smooth the boundaries between clusters and to fill holes inside clusters. After that, we compute six features for each cluster. These six features then go through a feature selection algorithm and three of them are determined to …


Modeling Habitat And Environmental Factors Affecting Mosquito Abundance In Chesapeake, Virginia, Alan Scott Bellows Jul 2007

Modeling Habitat And Environmental Factors Affecting Mosquito Abundance In Chesapeake, Virginia, Alan Scott Bellows

Biological Sciences Theses & Dissertations

The models I present in this dissertation were designed to enable mosquito control agencies in the mid-Atlantic region that oversee large jurisdictions to rapidly track the spatial and temporal distributions of mosquito species, especially those species known to be vectors of eastern equine encephalitis and West Nile virus. I was able to keep these models streamlined, user-friendly, and not cost-prohibitive using empirically based digital data to analyze mosquito-abundance patterns in real landscapes.

This research is presented in three major chapters: (II) a series of semi-static habitat suitability indices (HSI) grounded on well-documented associations between mosquito abundance and environmental variables, (III) …


Bio-Optical Properties Of The Arctic Waters: Empirical And Theoretical Observations, Jian Wang Apr 2004

Bio-Optical Properties Of The Arctic Waters: Empirical And Theoretical Observations, Jian Wang

OES Theses and Dissertations

Bio-optical observations were made during August 2000 in the Beaufort and Chukchi Seas. Chlorophyll a concentration (Chl) ranged from 0.068 to 18.51 mg chl m−3. Both total particulate and phytoplankton absorption at 443 nm were closely correlated with chlorophyll concentration. There is no strong correlation between chlorophyll concentration and absorption by soluble materials or nonpigmented particulates. Absorption, scattering, and attenuation all show strong first-order spectral relationships. Two semianalytical remote sensing reflectance models were evaluated and validated using bio-optical data collected in this region. Both models were proficient at retrieving chlorophyll concentration, phytoplankton absorption coefficients, and particulate backscattering coefficients. …


Satellite Evidence Of Hurricane-Induced Phytoplankton Blooms In An Oceanic Desert, S. M. Babin, J. A. Carton, T. D. Dickey, J. D. Wiggert Jan 2004

Satellite Evidence Of Hurricane-Induced Phytoplankton Blooms In An Oceanic Desert, S. M. Babin, J. A. Carton, T. D. Dickey, J. D. Wiggert

CCPO Publications

The physical effects of hurricanes include deepening of the mixed layer and decreasing of the sea surface temperature in response to entrainment, curl-induced upwelling, and increased upper ocean cooling. However, the biological effects of hurricanes remain relatively unexplored. In this paper, we examine the passages of 13 hurricanes through the Sargasso Sea region of the North Atlantic during the years 1998 through 2001. Remotely sensed ocean color shows increased concentrations of surface chlorophyll within the cool wakes of the hurricanes, apparently in response to the injection of nutrients and/or biogenic pigments into the oligotrophic surface waters. This increase in post-storm …


Atmospheric Water Vapor Lidar Measurements Using Analog And Photon Counting Techniques, Anuj Maheshkumar Shah Jul 2003

Atmospheric Water Vapor Lidar Measurements Using Analog And Photon Counting Techniques, Anuj Maheshkumar Shah

Electrical & Computer Engineering Theses & Dissertations

Atmospheric water vapor measurements are essential for the understanding of Earth's weather and radiation budget, along with the water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a commanding method used for water vapor measurements from aircraft, spaceborne, and ground-based platforms. The new unmanned aerial vehicle (UAV) water vapor DIAL system provides great feasibility due to the weight and size limitations. The system has significantly less weight, power consumption, and noise presence, thus making it great for UAV applications.

This thesis discusses a UAV water vapor DIAL system that was designed, developed, and evaluated. The research effort was …


New Evidence For Enhanced Ocean Primary Production Triggered By Tropical Cyclone, I. Lin, W. Timothy Liu, Chun-Chieh Wu, George T. F. Wong, Chuanmin Hu, Zhiqiang Chen, Wen-Der Liang, Yih Yang, Kon-Kee Liu Jan 2003

New Evidence For Enhanced Ocean Primary Production Triggered By Tropical Cyclone, I. Lin, W. Timothy Liu, Chun-Chieh Wu, George T. F. Wong, Chuanmin Hu, Zhiqiang Chen, Wen-Der Liang, Yih Yang, Kon-Kee Liu

OES Faculty Publications

[1] New evidence based on recent satellite data is presented to provide a rare opportunity in quantifying the long-speculated contribution of tropical cyclones to enhance ocean primary production. In July 2000, moderate cyclone Kai-Tak passed over the South China Sea (SCS). During its short 3-day stay, Kai-Tak triggered an average 30-fold increase in surface chlorophyll-a concentration. The estimated carbon fixation resulting from this event alone is 0.8 Mt, or 2-4% of SCS's annual new production. Given an average of 14 cyclones passing over the SCS annually, we suggest the long-neglected contribution of tropical cyclones to SCS's annual new production may …


Trichodesmium Spp.: Numerical Studies Of Resource Competition, Carbohydrate Ballasting, And Remote-Sensing Reflectance, Tonya Denise Clayton Jul 2001

Trichodesmium Spp.: Numerical Studies Of Resource Competition, Carbohydrate Ballasting, And Remote-Sensing Reflectance, Tonya Denise Clayton

OES Theses and Dissertations

In recent years, a new appreciation for the role of diazotrophy in the oceans has emerged. This dissertation reports on three modeling studies designed to investigate ecological processes associated with Trichodesmium spp., the most conspicuous marine diazotroph: (1) characterization of a generalized model Trichodesmium and issues of macronutrient resource competition; (2) carbohydrate ballasting by Trchodesmium and implications for the formation of surface accumulations; and (3) the vertical distribution of Trichodesmium and implications for detection from space.

The first study focuses on issues of nitrogen and phosphorus competition and ecosystem structure. It utilizes a simple ecosystem model that includes dissolved nitrogen …


A Compact Ozone Differential Absorption Lidar (Dial) Transmitter Using A Solid-State Dye Polymer, Alton L. Jones Jr. Apr 2001

A Compact Ozone Differential Absorption Lidar (Dial) Transmitter Using A Solid-State Dye Polymer, Alton L. Jones Jr.

Electrical & Computer Engineering Theses & Dissertations

The measurement of atmospheric ozone is important because in the troposphere it is a pollutant that is toxic to living systems, but in the stratosphere ozone protects life by shielding us from the sun's harmful UV-B radiation.

Laser remote sensing from aircraft using differential absorption lidar (DIAL) has become a very important technique for measuring atmospheric ozone at different altitudes and locations. Current aircraft-based DIAL systems use pulsed Nd:YAG pumped liquid dye lasers, which are then frequency doubled into the UV region, to probe both the stratosphere and troposphere for ozone.

This thesis describes a new potential DIAL laser transmitter …


Wavelength Modulation Spectroscopy Of Water Vapor And Line Center Stabilization At 1.462 Μm For Lidar Applications, Colleen Marie Fitzgerald Apr 2000

Wavelength Modulation Spectroscopy Of Water Vapor And Line Center Stabilization At 1.462 Μm For Lidar Applications, Colleen Marie Fitzgerald

Electrical & Computer Engineering Theses & Dissertations

Wavelength modulation spectroscopy was employed to investigate water vapor absorption lines in the 1.462 µm wavelength region using an external-cavity diode laser. These measurements were necessary in the development of a lidar (light detection and ranging) instrument for differential absorption measurement of the concentration and movement of water vapor in the Earth's atmosphere. Differential absorption measurements require that the laser frequency remain stable throughout the duration of the measurement. To ensure this stability, the laser output wavelength is monitored and a feedback control loop set up to minimize laser line drift. Three lines were investigated in the 1.462 µm region. …


Fiber-Optic Coupled Lidar Receiver System To Measure Stratospheric Ozone, David Brent Harper Apr 1999

Fiber-Optic Coupled Lidar Receiver System To Measure Stratospheric Ozone, David Brent Harper

Electrical & Computer Engineering Theses & Dissertations

A fiber-optic coupled lidar receiver system was constructed to determine ozone concentrations in the stratosphere. The system was used to make ground-based measurements of lidar returns from a UV DIAL system. A fiber-optic cable was used to couple the light from the receiver telescope to the light detector. Photon counting was implemented as the light detection technique. This technique allowed detection of 301 and 311 nm lidar returns up to 27.5 and 32.5 km respectively. A software application was developed to control the photon counting system and perform real-time data analysis of measured lidar returns. DIAL measurements of stratospheric ozone …


Analysis Of Lunar Basalt Flows In Oceanus Procellarum Using Clementine Data, Noel William Jackson Apr 1999

Analysis Of Lunar Basalt Flows In Oceanus Procellarum Using Clementine Data, Noel William Jackson

OES Theses and Dissertations

Remote sensing analyses of data set taken by Clementine in 1994 permit new observations about mineral distribution on the lunar surface, basalt flow stratigraphy, and thus the geologic evolution of the Moon. The northern section of Oceanus Procellarum contains numerous impact craters which penetrated the basalt and thus can be used as natural probes to estimate the number and thicknesses of flows.

I constructed a mosaic taken in three frequencies ( 415 nm, 750 nm, 950 nm), and a Ratio Image (750/415 = red, 750/950 = green, 415/750 = blue). On such an image, red indicates the iron-poor mature highland …


Ocean Surface Maps From Blending Disparate Data Through Normal Mode Analysis, William John Schulz Jr. Jan 1999

Ocean Surface Maps From Blending Disparate Data Through Normal Mode Analysis, William John Schulz Jr.

OES Theses and Dissertations

Rapid environmental assessment is conducted using disparate data sources in the northwestern Gulf of Mexico. An overview of significant physical features in the Gulf highlights the complexities of the large and meso-scale circulations. Spectral analysis of high resolution current meter and drifter data reveals the significant forcing features detectable by readily available observing techniques. These observations are combined with boundary data extracted from the U.S. Navy's Modular Ocean Data Assimilation System (MODAS) through Normal Mode Analysis (NMA). The NMA blending process is described, and surface maps of velocity and convergence are produced. Using statistical and qualitative techniques, the NMA generated …


Inversion And Analysis Of Remotely Sensed Atmospheric Water Vapor Measurements At 940nm, Jack Cutler Larsen Apr 1998

Inversion And Analysis Of Remotely Sensed Atmospheric Water Vapor Measurements At 940nm, Jack Cutler Larsen

Mechanical & Aerospace Engineering Theses & Dissertations

The understanding and acceptance of remotely sensed atmospheric data depends strongly on the steps taken to characterize experiment error and validate observations through comparisons to other independent measurements. A formal error analysis of the Stratospheric Aerosol and Gas Experiment II (SAGE II) water vapor operational inversion algorithm is performed and compared to previous results. Random measurement errors were characterized by segmented least-squares profile fitting of the slant path absorption which found the error to be uncorrelated in the stratosphere with estimated variances significantly smaller than expected from 18-30 km. Estimates of null space error were developed from radiosonde hygrometers in …


Development Of A Photon Counting System For Ozone Differential Absorption Lidar Signal Detection, Bradley Allen Eccles Jul 1997

Development Of A Photon Counting System For Ozone Differential Absorption Lidar Signal Detection, Bradley Allen Eccles

Electrical & Computer Engineering Theses & Dissertations

A photon counting system was assembled and integrated into an existing ozone differential absorption lidar signal detection system to improve the range of ozone measurement. Results of data extraction from decaying ozone return signals are presented. Photomultiplier tube detector models EMI 9214Q and EMI 9B17Q are evaluated and characterized. Detector operating performance was based on tube quantum efficiency, gain, dark current, and linearity. The influence of photomultiplier tube characteristics on photon counting performance are discussed along with the recommended optimum photon counting operating conditions. Two photomultiplier gating schemes, focus grid and four dynode gating, are described for use in photon …


Observation Of Shelfwater Overrunning The Southern Slope Sea, Ajoy Kumar Apr 1996

Observation Of Shelfwater Overrunning The Southern Slope Sea, Ajoy Kumar

OES Theses and Dissertations

Analyses of two years (1992 and 1993) of high resolution (1.47 km2) sea surface temperature satellite images of the southern Mid-Atlantic Bight (MAB), showed that unusually extensive overhang of shelf water occurs episodically, and coherently over along shelf distances of several hundred kilometers. These episodes are dubbed overrunning of the Slope Sea by shelf water. The overrunning volume has a "face" and a "back" (southern and northern limit). It transports substantial quantities of shelf water southward, and does not retreat onto the shelf, but eventually joins the western edge of the Gulf Stream in the vicinity of Chesapeake …


A Total Systems Analysis Method For The Conceptual Design Of Spacecraft: An Application To Remote Sensing Imager Systems, Knut I. Oxnevad Apr 1996

A Total Systems Analysis Method For The Conceptual Design Of Spacecraft: An Application To Remote Sensing Imager Systems, Knut I. Oxnevad

Engineering Management & Systems Engineering Theses & Dissertations

Increased emphasis is being placed on improving the performance of space projects, within tighter budgets and shorter development times. This has led to a need for more efficient space system design methods. The research described here represents an effort to develop and evaluate such a method.

Systems engineering and concurrent engineering together provide the theoretical foundation for the method. The method, derived from both this theoretical foundation and ideas from experts in the space industry, emphasizes a total systems analysis approach, taking into account given mission requirements, and the mathematical modeling of interactions between system variables and between subsystems. The …


Autonomous Robot Navigation In Unknown Terrains Using Parallel Numerical Artificial Potential Fields, John C. Schneider Dec 1994

Autonomous Robot Navigation In Unknown Terrains Using Parallel Numerical Artificial Potential Fields, John C. Schneider

Computer Science Theses & Dissertations

We present a new artificial potential field formulation for resolution complete robot navigation that unifies the purely geometric path planning problem with the lower level force control problem. Our formulation is designed for numerical computation over a massively parallel mesh of processors and is responsive to newly discovered terrain features. It does not suffer from many of the problems commonly associated with potential fields and with adequate resolution provides provably correct, collision free convergence to the goal. In addition, our formulation supports many desirable, practical features required for implementation, such as bounded actuator torques, attainable incremental constructability, realizable computation and …