Lewis Link | University of Maryland, College Park (original) (raw)

Papers by Lewis Link

Proceedings of SPIE, Sep 22, 1983

Since 1977 the NASA Airborne Oceanographic Lidar (AOL) has been utilized to evaluate the potentia... more Since 1977 the NASA Airborne Oceanographic Lidar (AOL) has been utilized to evaluate the potential of airborne lidar systems for a variety of marine and terrestrial applications. The AOL is designed as a flying laser laboratory with flexibility that allows rapid modification of transmitter and receiver optical configurations as well as operation with various lasers. This flexibility in design has permitted the use of the AOL for numerous types of investigations in differing and often unrelated disciplines. The AOL can can be operated in two basic modes; backscattered signals can be temporally resolved and recorded in the bathymetric mode, while in the fluorescensing mode returning on-wavelength, water Raman, and laser induced flourescence response signals are spectrally resolved. Results of investigations conducted during the past several years over marine and terrestrial targets are discussed along with planned improvements to the lidar system. Results are presented for terrain, shoreline, and ice topography, and hydrography performed in the bathymetric mode as well as for chlorophyll a and phytoplankton photopigment investigations performed in the fluorosensing mode.

Advances in Space Research, 1983

The state of the art of operating airborne laser mapping systems ¡s summar¡zed; also summarized a... more The state of the art of operating airborne laser mapping systems ¡s summar¡zed; also summarized afe the results of f¡eld exper¡ments aenducted to evaluate system performance capabilities. The proiected capabil¡t¡es of systems c-tlrrently under development and pro¡ected for operational testing ¡n the near future are contrasted to the capabilities estãblished for the operat¡ng systems. Current oonstraints on improving performance a¡e identified and discussed with respect to ¡ndividual system components {i.e., lasers, data record¡ng and pro' cêss¡ng systems, posit¡on¡ng systems, and ¡nformat¡on display systems). A prospectus on the performance of future laser mapp¡ng systems is provided for spec¡fic technology advances.

… Engineering and remote …, 1984

WB KRABILL, JG COLLINS, LE LINK, RN SWIFT, ML BUTLER Photogrammetric Engineering and Remote Sensi... more WB KRABILL, JG COLLINS, LE LINK, RN SWIFT, ML BUTLER Photogrammetric Engineering and Remote Sensing 50, 685-694, 6/1984. ... Results from surveys conducted under winter 'leaves off' and summer 'leaves on' conditions, aspects of day and night operation, and data ...

Water Policy, 2021

Following Hurricane Katrina, the US Army Corps of Engineers, supported in part by the risk and re... more Following Hurricane Katrina, the US Army Corps of Engineers, supported in part by the risk and reliability analysis conducted by the Interagency Performance Evaluation Task Force (IPET), made a major shift from ‘protection’ to ‘risk reduction’ as the principal goal in flood mitigation. The mitigation of the flood risk in Southeast Louisiana was embodied in the design and construction of the ‘Hurricane and Storm Damage Risk Reduction System’, the post-Katrina initiative for New Orleans flood mitigation. It also spawned a major overhaul of many of the Corps of Engineers’ technical guidance and engineering practice documents, incorporating risk as a key measure in the planning and design processes. The criteria applied for the design of the HSDRRS are discussed, with summaries of the associated major changes in Corps engineering guidance and practice relevant to flood mitigation.

Commercially available data collected by U.S. and French satellites re helping civil engineers ta... more Commercially available data collected by U.S. and French satellites re helping civil engineers take a closer look at our planet. Also available are PC-based image processing systems that provide relatively powerful analysis capabilities at reasonable costs. To use these resources in a cost effective way, the engineer needs a basic understanding of the operating principles of the satellite sensors as well as the types of terrain features that are readily mapped from space imagery. Capabilities of available hardware and software are noted. The technology is still so new that much of the work can be called experimental, but civil engineering applications range from land use surveys for urban planning and flood control, to monitoring turbidity at dredge spoil sites.

: Military hydrology is a specialized area of study that deals with the characteristics of surfac... more : Military hydrology is a specialized area of study that deals with the characteristics of surface and subsurface water features that may affect the planning and conduct of military operations. A study was conducted to establish the military's requirements for hydrologic information, to evaluate existing capabilities, and to develop a plan of research. As indicated by doctrine, responses to inquiries, and recent investigations by other agencies, military requirements for hydrologic data are extensive in terms of scope, accuracy, and response time. Evaluations of Army and civilian capabilities in the field of hydrology were made; with reference to the Army, the evaluations revealed an absence of modern methodologies, inadequate resources, and a lack of trained personnel. A research plan was developed to provide a short-term update of military hydrology based on adaptations of existing civilian technologies and a long-term advancement in capabilities through improved technologies....

: The systematic application of remote sensing techniques at Fort Carson has provided critical in... more : The systematic application of remote sensing techniques at Fort Carson has provided critical information for the environmental management of vehicle-maneuver training areas. The remote sensing simulation model provided a quantitative means for selecting the best film-filter combination for the job. Only one type of information was extracted from remotely sensed data for the purposes of this example; the techniques and systematic procedures followed herein could easily be applied to more complex studies requiring other types of information. It must be emphasized that the application of remote sensing to a specific problem must be closely allied with the specific data requirements necessary for the solution of the problem. Accuracy, scale, and threshold values considered critical for detection must be identified prior to the conduct of the remote sensing mission to allow adequate planning of the data acquisiton program, both on the ground and with remote sensor systems. (Author)

: Camouflage and target acquisition have opposing functions, one to hide and the other to seek. T... more : Camouflage and target acquisition have opposing functions, one to hide and the other to seek. They have a common denominator, however, in that the features that surround the target to be camouflaged or identified (sometimes called the background) are critical in both the hide and seek role. An equally intimate knowledge is needed of the characteristics of both the target and the background. In essence, making something match the background and discriminating something from the background are inverse problems that require the same technology. In the past decade thermal infrared (IR) technology has come of age providing sensors with new capabilities for target acquisition and presenting a new threat for camouflage. Optimizing IR sensors for target acquisition or optimizing camouflage measures to defeat such sensors requires a quantitative understanding of the thermal IR signatures of both targets and backgrounds. The Army-Wide Ground Target Signature Program (AWGTSP) is addressing t...

: Field data were collected to establish seismic response characteristics, their distribution, an... more : Field data were collected to establish seismic response characteristics, their distribution, and the environmental factors that control them in two Army Tropic Test Center seismic sensor test areas (Gamboa and Alpha) in the Panama Canal Zone. Detailed seismic and environmental data are presented, and special seismic response tests (drop-hammer, man-walking, and ambient-noise) conducted in various environmental conditions at 9 sites in the Gamboa test area and 13 sites in the Alpha test area are described. Also discussed are the results (empirical regression equations) of a multicorrelation analysis used to relate the seismic response descriptors (peak particle velocity, peak summed particle velocity, and frequency) to the environmental parameters; the techniques used for mapping the seismic responses in the test areas; and the techniques for interpreting the seismic responses and terrain factor maps in terms of seismic intrusion detector performance. Results show that the seismic ...

: The purpose of this effort is to provide the smart weapons and autonomous target recognition (A... more : The purpose of this effort is to provide the smart weapons and autonomous target recognition (ATR) communities with a validated capability to integrate: measurements, information bases, modeling and scene simulation; to effectively consider and exploit the complex environment of world wide battlefields. Information and analytical tools that comprehensively treat the environment in terms significantly relevant to weapon and sensor performance will be developed and demonstrated for two primary user communities: designers/developers' and 'testers/evaluators. The short term goals (91-92), long term goals (93-96), relationship to other programs, transition, program tasks and associated tasks are explained in this program implementation plan.

: Sequential color-infrared aerial photos and corresponding surface water samples were obtained a... more : Sequential color-infrared aerial photos and corresponding surface water samples were obtained at selected sites on the Illinois and Upper Mississippi Rivers to examine the movement of tow-generated suspended material plumes. The aerial photos were digitized with a scanning microdensitometer, and optical density values were extracted for correlation with suspended material concentration data obtained by laboratory analysis of the water samples. Correlation of the optical density and concentration values for each site and for sample positions at each site did not produce a statistically significant relation between the variables. The poor correlation between optical density and concentration values prevented quantitative definition from the imagery of the distribution of suspended material concentrations at the sites as a function of time. Digital data handling procedures were used to enhance the visibility on the imagery of the tow-generated plumes. The procedures applied were succ...

Civil Engineering Magazine Archive

International Journal of Science and Research (IJSR)

River water in the provinces of Muthanna and Qadisiyah, And of total dissolved solids, locate fou... more River water in the provinces of Muthanna and Qadisiyah, And of total dissolved solids, locate fourteen station to measure river water pollution from the date of 01.11.2014 -31.10.2015 in addition to the identification of agricultural drainage and sewage sites nominated ground water and soil of the two provinces, And used Satellite imagery taken by sensor Ortho PMS with highest resolution 1.5 m and produced in the first package (pand 1) wavelength 0.455-0.525 Maekeromitr second package (pand 2) wavelength 0.530-0.590 Maekeromitr third package (pand 3) with a wavelength of 0.625 -0.695 Maekeromitr and fourth package (pand 4) 0.760-0.