California's topography poses challenges for road builders. Northwest of Los Angeles, deformation of Earth's crust along the Pacific-North American crustal plate boundary has made transportation difficult. Direct connection between metropolitan Los Angeles (image lower left) and California's Central Valley (image top center) through the rugged terrain seen on the left side of this image was long avoided in favor of longer but easier paths. However, over the last century, three generations of roads have traversed this terrain. The first was 'The Ridge Route', a two-lane road, built in 1915, which followed long winding ridge lines that included 697curves. The second, built in 1933, was to become four-lane U.S. Highway 99. It generally followed widened canyon bottoms. The third is the current eight lane Interstate 5 freeway, built in the 1960s, which is generally notched into hillsides, but also includes a stretch of several miles where the two directions of travel are widely separated and driving is 'on the left', a rarity in the United States. Such an unusual highway configuration was necessary in order to optimize the road grades for uphill and downhill traffic in this topographically challenging setting.This anaglyph was generated by first draping a Landsat satellite image over a preliminary topographic map from the Shuttle Radar Topography Mission, then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30 meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive.The elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.Size: 141 by 107 kilometers (88 by 66 miles) Location: 34.5 deg. North lat., 118.7 deg. West lon. Orientation: North toward upper right Image: Landsat bands 1,2,3 averaged (visible light as grey) Date Acquired: February 16, 2000 (SRTM), November 11, 1986 (Landsat) Image: NASA/JPL/NIMA
Antelope Valley is bounded by two of the most active faults in California: the Garlock fault, which fronts the distant mountains in this view, and the San Andreas fault, part of which is seen bounding the mountains in the left foreground. In this view, Antelope Valley is in the foreground, the Tehachapi Mountains form the left skyline, and ranges within the southernmost Sierra Nevada form the right skyline. Antelope Valley is directly north of Los Angeles and is the westernmost part of the Mojave Desert. It is a closed basin. Stream flow here ends at Rosamond and Rogers dry lakes, which appear bright white. Dry lakes like these are common where tectonic activity raises and lowers parts of the Earth's crust, and thus the topographic surface, faster than stream flow can fill depressions with water, and then overflow and cut escape channels to other basins and eventually to the sea. The Sierra Nevada, the Tehachapi, and other mountains generally to the west create a rain shadow desert here. Thus, the area definitely has the active tectonics and low rainfall combination that leads to closed basin topography.This perspective view was generated by draping a Landsat satellite image over a preliminary topographic map from the Shuttle Radar Topography Mission. Shading of the SRTM elevation model was added to enhance topographic appearance. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30 meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive.The elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington DC.Size: 92 kilometers (57 miles) view width, 87 kilometers (54 miles) view distance Location: 34.9 deg. North lat., 118.3 deg. West lon. Orientation: View toward the northwest, 3X vertical exaggeration Image: Landsat bands 1, 2+4, 3 in blue, green, red, respectively, plus DEM shading. Date Acquired: February 16, 2000 (SRTM), November 11, 1986 (Landsat) Image: NASA/JPL/NIMA
This perspective view shows the Caribbean coastal plain of Costa Rica, with the Cordillera Central rising in the background and the Pacific Ocean in the distance. The prominent river in the center of the image is the Rio Sucio, which merges with the Rio Sarapiqui at the bottom of the image and eventually joins with Rio San Juan on the Nicaragua border.Like much of Central America, Costa Rica is generally cloud covered so very little satellite imagery is available. The ability of the Shuttle Radar Topography Mission (SRTM) instrument to penetrate clouds and make three-dimensional measurements will allow generation of the first complete high-resolution topographic map of the entire region. These data were used to generate the image.This three-dimensional perspective view was generated using elevation data from SRTM and an enhanced false-color Landsat 7 satellite image. Colors are from Landsat bands 5, 4, and 2 as red, green and blue, respectively. Topographic expression is exaggerated two times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, S.D.Elevation data used in this image was acquired by the SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.Size: scale varies in this perspective image Location: 10.4 degrees North latitude, 84.0 degrees West longitude Orientation: looking Southwest Image Data: Landsat Bands 5, 4, 3 as red, green, blue respectively Original Data Resolution: SRTM 30 meters (99 feet) Date Acquired: February 2000 (SRTM)
Honolulu, on the island of Oahu, is a large and growing urban area with limited space and water resources. This perspective view, combining a Landsat image with SRTM topography, shows how the topography controls the urban growth pattern, causes cloud formation, and directs the rainfall runoff pattern. Features of interest in this scene include downtown Honolulu (right), Honolulu Harbor (right), Pearl Harbor (center), and offshore reef patterns (foreground). The Koolau mountain range runs through the center of the image. On the north shore of the island are the Mokapu Peninsula and Kaneohe Bay (upper right). Clouds commonly hang above ridges and peaks of the Hawaiian Islands, and in this rendition appear draped directly on the mountains. The clouds are actually about 1000 meters (3300 feet) above sea level. High resolution topographic and image data allow ecologists and planners to assess the effects of urban development on the sensitive ecosystems in tropical regions.This type of display adds the important dimension of elevation to the study of land use and environmental processes as observed in satellite images. The perspective view was created by draping a Landsat 7 satellite image over an SRTM elevation model. Topography is exaggerated about six times vertically. The Landsat 7 image was acquired on February 12, 2000, and was provided by the United States Geological Survey's Earth Resources Observations Systems (EROS)Data Center, Sioux Falls, South Dakota.The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI) space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.Size: 28 by 56 kilometers (17 by 35 miles) Location: 21.4 deg. North lat., 157.8 deg. West lon. Orientation: Looking North Original Data Resolution: SRTM, 30 meters (99 feet); Landsat, 15 meters (50 feet) Date Acquired: SRTM, February 18, 2000; Landsat February 12, 2000 Image: NASA/JPL/NIMA
Mount Kilimanjaro (Kilima Njaro or 'shining mountain' in Swahili), the highest point in Africa, reaches 5,895 meters (19,340 feet) above sea level, tall enough to maintain a permanent snow cap despite being just 330 kilometers (210 miles) south of the equator. It is the tallest free-standing mountain on the Earth's land surface world, rising about 4,600 meters (15,000 feet) above the surrounding plain. Kilimanjaro is a triple volcano (has three peaks) that last erupted perhaps more than 100,000 years ago but still exudes volcanic gases. It is accompanied by about 20 other nearby volcanoes, some of which are seen to the west (left) in this view, prominently including Mount Meru, which last erupted only about a century ago. The volcanic mountain slopes are commonly fertile and support thick forests, while the much drier grasslands of the plains are home to elephants, lions, and other savanna wildlife.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM), a Landsat 7 satellite image, and a false sky. Topographic expression is vertically exaggerated two times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.Size: View width 124 kilometers (77 miles), View distance 166 kilometers (103 miles) Location: 3 degrees South latitude, 37 degrees East longitude Orientation: View North, 2 degrees below horizontal, 2 times vertical exaggeration Image Data: Landsat Bands 3, 2+4, 1 as red, green, blue, respectively. Original Data Resolution: SRTM 1 arc-second (30 meters or 98 feet), Thematic Mapper 30 meters (98 feet) Date Acquired: February 2000 (SRTM), A February 21, 2000 (Landsat 7)
This 3-D view of a coastal area in southernmost Oman shows how topographic information can be used to enhance satellite images, deriving a better understanding of the processes that sculpt the landscape. The coastline in the upper half of the image appears to follow the same trend as a canyon in the lower half of the image. Both features are probably coincident with a single fault that cuts the limestone bedrock. Note how in this climate limestone erodes sharply along the stream courses resulting in deep and narrow canyons. Generally the landscape is barren, but the darker areas have sparse vegetation that is supported by summer monsoon moisture. The Arabian Sea is on the right.This anaglyph was generated by first draping a Landsat Thematic Mapper image over a topographic map from the Shuttle Radar Topography Mission, then using the topographic data to create two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30 meter (100 foot) spatial resolution of most Landsat images and will provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, South Dakota.The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI)space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.Size: 20.5 by 18.3 kilometers (12.7 by 11.3 miles) Location: 16.9 deg. North lat., 53.7 deg. East lon. Orientation: North at top-left Date Acquired: February 15, 2000 Image: NASA/JPL/NIMA
Prominently displayed in this image, Mt. Pinos, at 2,692 meters (8,831 feet) is the highest peak in the Los Padres National Forest. Named for the mantle of pine trees covering its slopes and summit, it offers one of the best stargazing sites in Southern California. Shuttle Radar Topography Mission (SRTM) elevation data were combined with Landsat data to generate this perspective view looking toward the northwest. Not only is the mountain popular with astronomers and astro-photographers, it is also popular for hiking trails and winter sports.The broad low relief area in the right foreground is Cuddy Valley. Cuddy Valley Road is the bright line on the right (north)side of the valley. Just to the left and paralleling the road is a scarp (cliff) formed by the San Andreas fault. The fault slices through the mountains here and then bends and continues onto the Carrizo Plain (right center horizon). This entire segment of the San Andreas fault broke in a major earthquake in 1857.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data match the 30-meter(98-foot) resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors approximate natural colors.The elevation data used in this image was acquired by SRTM aboard Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.Distance to Horizon: 176 kilometers (109 miles) Location: 34.8 deg. North lat., 119.1 deg. West lon. View: Toward the Northwest Date Acquired: February 16, 2000 SRTM, December 14, 1984 Landsat
The city of Palm Springs nestles at the base of Mount San Jacinto in this computer-generated perspective viewed from the east. The many golf courses in the area show up as irregular green areas while the two prominent lines passing through the middle of the image are Interstate 10 and the adjacent railroad tracks. The San Andreas Fault passes through the middle of the sandy Indio Hills in the foreground.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM) and an enhanced color Landsat 5satellite image. Topographic expression is exaggerated two times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C.Size: scale varies in this perspective image Location: 33.8 deg. North lat., 116.3 deg. West lon. Orientation: looking west Image Data: Landsat Bands 3, 2, 1 as red, green, blue, respectively Original Data Resolution: SRTM 1 arcsecond (30 meters or 98 feet), Thematic Mapper 1 arcsecond (30 meters or 98 feet) Date Acquired: February 2000 (SRTM)
Santa Barbara, California, is often called 'America's Riviera.' It enjoys a Mediterranean climate, a mountain backdrop, and a long and varied coastline. This perspective view of the Santa Barbara region was generated using data from the Shuttle Radar Topography Mission (SRTM) and an enhanced Landsat satellite image. The view is toward the northeast, from the Goleta Valley in the foreground to a snow-capped Mount Abel (elevation 2526 m or 8286 feet) along the skyline. The coast here generally faces south. Consequently, Fall and Winter sunrises occur over the ocean, which is unusual for the U.S. west coast. The Santa Barbara 'back country' is very rugged and largely remains as undeveloped wilderness and an important watershed for local communities. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data match the 30-meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors approximate natural colors.The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface.To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200-feet) long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif, for NASA's Earth Science Enterprise,Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.Location (Isla Vista): 34.41 deg. North lat., 119.85 deg. West lon. View: East Scale: Scale Varies in this Perspective Date Acquired: February 16, 2000 SRTM, December 14, 1984 Landsat
This image of the Santa Barbara, California, region provides a beautiful snapshot of the area's rugged mountains and long and varied coastline. Generated using data acquired from the Shuttle Radar Topography Mission (SRTM) and an enhanced Landsat image this is a perspective view toward the northeast, from the Goleta Valley in the foreground to a snow-capped Mount Abel (elevation 2,526 m or 8,286 feet) along the skyline at the left. On a clear day, a pilot might see a similar view shortly before touching down on the east-west runway of the Santa Barbara Airport, seen just to the left of the coastline near the center of image. This area is one of the few places along the U.S. West Coast where because of a south-facing beach, fall and winter sunrises occur over the ocean.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data match the 30-meter(98-foot) resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors approximate natural colors.The elevation data used in this image was acquired by SRTM aboard Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200-feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif, for NASA's Earth Science Enterprise, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.Location: 34.5 deg. North lat., 119.75 deg. West lon. View: Northeast Scale: Scale Varies in this Perspective Date Acquired: February 16, 2000 SRTM, December 14, 1984 Landsat
Southern California's dramatic topography plays acritical role in its climate, hydrology, ecology, agriculture, and habitability. This image of Southern California, from the desert at Mojave to the ocean at Ventura, shows a variety of landscapes and environments. Winds usually bring moisture to this area from the west, moving from the ocean, across the coastal plains, to the mountains, and then to the deserts. Most rainfall occurs as the air masses rise over the mountains and cool with altitude. Continuing east, and now drained of their moisture, the air masses drop in altitude and warm as they spread across the desert. The mountain rainfall supports forest and chaparral vegetation, seen here, and also becomes ground water and stream flow that supports citrus, avocado, strawberry, other crops, and a large and growing population on the coastal plains.This perspective view was generated by draping a Landsat satellite image over a preliminary topographic map from the Shuttle Radar Topography Mission. It shows the Tehachapi Mountains in the right foreground, the city of Ventura on the coast at the distant left, and the eastern most Santa Ynez Mountains forming the skyline at the distant right.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30 meter resolution of most Landsat images and will substantially help in analyses of the large and growing Landsat image archive.The elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington DC.Size: 43 kilometers (27 miles) view width, 166 kilometers (103 miles) view distance Location: 34.8 deg. North lat., 118.8 deg. West lon. Orientation: View toward the southwest, 3X vertical exaggeration Image: Landsat bands 1, 2&4, 3 as blue, green, and red, respectively Date Acquired: February 16, 2000 (SRTM), November 11, 1986 (Landsat) Image: NASA/JPL/NIMA
San Joaquin, the name given to the southern portion of California's vast Central Valley, has been called the world's richest agricultural valley. In this perspective view generated using data from the Shuttle Radar Topography Mission and an enhanced Landsat image, we are looking toward the southwest over a checkerboard pattern of agricultural fields. Mt. Pinos, a popular location for stargazing at 2,692 meters (8,831 feet) looms above the valley floor and is visible on the left side of the image. The productive southern San Joaquin is in reality a desert, averaging less than 12.7 cm (5 inches) of rain per year. Through canals and irrigation, the region nurtures some two hundred crops including grapes, figs, apricots, oranges, and more than 4,047 square-km (1,000,000 acres) of cotton. The California Aqueduct, transporting water from the Sacramento River Delta through the San Joaquin, runs along the base of the low-lying Wheeler Ridge on the left side of the image. The valley is not all agriculture though. Kern County, near the valley's southern end, is the United States' number one oil producing county, and actually produces more crude oil than Oklahoma. For visualization purposes, topographic heights displayed in this image are exaggerated two times. Colors, from Landsat data, approximate natural color.The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif, for NASA's Earth Science Enterprise,Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.Location: 35.08 deg. North lat., 119.00 deg. West lon. View: Toward the Southwest Scale: Scale Varies in this Perspective Date Acquired: February 16, 2000 SRTM, December 14, 1984 Landsat
After draining the northern flank of the Alps Mountains in Germany and Austria, the Danube River flows east as it enters this west-looking scene (upper right) and forms the border between Slovakia and Hungary. The river then leaves the border as it enters Hungary and transects the Transdanubian Mountains, which trend southwest to northeast. Upon exiting the mountains, the river turns southward, flowing past Budapest (purplish blue area) and along the western margin of the Great Hungarian Plain.South and west of the Danube, the Transdanubian Mountains have at most only about 400 meters (about 1300 feet) of relief but they exhibit varied landforms, which include volcanic, tectonic, fluvial (river), and eolian (wind) features. A thick deposit of loess (dust deposits likely blown from ancient glacial outwash) covers much of this area, and winds from the northwest, funneled between the Alps and the Carpathian Mountains, are apparently responsible for a radial pattern of erosional streaks across the entire region.This image was generated from a Landsat satellite image draped over an elevation model produced by the Shuttle Radar Topography Mission (SRTM). The view uses a 3-times vertical exaggeration to enhance topographic expression. The false colors of the scene result from displaying Landsat bands 1, 4, and 7 in blue, green, and red, respectively. Band 1 is visible blue light, but bands 4 and 7 are reflected infrared light. This band combination maximizes color contrasts between the major land cover types, namely vegetation (green), bare ground (red), and water (blue). Shading of the elevation model was used to further highlight the topographic features.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.View Size: 133 kilometers (82 miles) wide, 90 kilometers (56 miles) distance Location: 47.5 degrees North latitude, 19.0 degrees East longitude Orientation: Looking West, 15 degrees down from horizontal, 3X vertical exaggeration Image Data: Landsat Bands 1, 4, 7 as blue, green, red respectively Date Acquired: February 2000 (SRTM), October 11, 1990 (Landsat)
On May 9, 2000, the Landsat 7 satellite acquired an image of the area around Los Alamos, New Mexico. The Landsat 7 satellite acquired this image from 427 miles in space through its sensor called the Enhanced Thematic Mapper Plus (ETM+). Evident within the imagery is a view of the ongoing Cerro Grande fire near the town of Los Alamos and the Los Alamos National Laboratory. Combining the high-resolution (30 meters per pixel in this scene) imaging capacity of ETM+ with its multi-spectral capabilities allows scientists to penetrate the smoke plume and see the structure of the fire on the surface. Notice the high-level of detail in the infrared image (bottom), in which burn scars are clearly distinguished from the hotter smoldering and flaming parts of the fire. Within this image pair several features are clearly visible, including the Cerro Grande fire and smoke plume, the town of Los Alamos, the Los Alamos National Laboratory and associated property, and Cerro Grande peak. Combining ETM+ channels 7, 4, and 2 (one visible and two infrared channels) results in a false color image where vegetation appears as bright to dark green (bottom image). Forested areas are generally dark green while herbaceous vegetation is light green. Rangeland or more open areas appear pink to light purple. Areas with extensive pavement or urban development appear light blue or white to purple. Less densely-developed residential areas appear light green and golf courses are very bright green. The areas recently burned appear black. Dark red to bright red patches, or linear features within the burned area, are the hottest and possibly actively burning areas of the fire. The fire is spreading downslope and the front of the fire is readily detectable about 2 kilometers to the west and south of Los Alamos. Combining ETM+ channels 3, 2, and 1 provides a true-color image of the greater Los Alamos region (top image). Vegetation is generally dark to medium green. Forested areas are very dark green while herbaceous vegetation is medium green. Rangeland or more open areas appear as tan or light brown. Areas with extensive pavement or urban development appear white to light green. Less densely-developed residential areas appear medium green and golf courses are medium green. The fires and areas recently burned are obscured by smoke plumes which are white to light blue. Landsat 7 data are archived and available from EDC. Image by Rob Simmon, Earth Observatory, NASA Goddard Space Flight Center. Data courtesy Randy McKinley, EROS Data Center (EDC)
Digital elevation models (DEMs), such as those produced by the Shuttle Radar Topography Mission (SRTM), allow user-controlled visualization of the Earth's landforms that is not possible using satellite imagery alone. This three-view comparison shows Los Angeles, Calif., and vicinity, with a Landsat image (only) on the left, a shaded relief rendering of the SRTM DEM on the right, and a merge of the two data sets in the middle. Note that topographic expression in the Landsat image alone is very subtle due to the fairly high sun angle (63 degrees above the horizon) during the satellite overflight in late morning of a mid-Spring day (May 4, 2001). In contrast, computer generated topographic shading of the DEM provides a pure and bold image of topographic expression with a user specified illumination direction. The middle image shows how combining the Landsat and DEM shaded relief can result in a topographically enhanced satellite image in which the information content of both data sets is merged into a single view.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and helps in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.Size: 138.8 kilometers (86.1 miles) by 94.0 kilometers (58.3 miles) Location: 34.1 degrees North latitude, 118.3 degrees West longitude Orientation: North at top Image Data: Landsat bands 3, 2+4, 1 as red, green, blue, respectively, with SRTM shaded relief, plus Landsat panchromatic band 8 added for detail. Original Data Resolution: SRTM 1 arc-second (30 meters or 98 feet), Landsat color 30 meters (98 feet) sharpened with Landsat panchromatic band (15 meters or 49 feet). Date Acquired: May 4, 2001 (Landsat), February 2000 (SRTM)
The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This computer generated perspective image provides a northward looking 'view from space' that includes all of these Olympic sites. In the south, next to Utah Lake, Provo hosts the ice hockey competition. In the north, northeast of the Great Salt Lake, Ogden hosts curling, and the nearby Snow Basin ski area hosts the downhill events. In between, southeast of the Great Salt Lake, Salt Lake City hosts the Olympic Village and the various skating events. Further east, across the Wasatch Mountains, the Park City area ski resorts host the bobsled, ski jumping, and snowboarding events. The Winter Olympics are always hosted in mountainous terrain. This view shows the dramatic landscape that makes the Salt Lake City region a world-class center for winter sports.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM) and a Landsat 5 satellite image mosaic. Topographic expression is exaggerated four times.For a full-resolution, annotated version of this image, please select Figure 1, below: [figure removed for brevity, see original site] Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter(approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.Size: View width 48.8 kilometers (30.2 miles), View distance 177 kilometers (110 miles) Location: 41 deg. North lat., 112.0 deg. West lon. Orientation: View North, 20 degrees below horizontal Image Data: Landsat Bands 3, 2, 1 as red, green, blue, respectively. Original Data Resolution: SRTM 1 arcsecond (30 meters or 98 feet), Thematic Mapper 30 meters (98 feet) Date Acquired: February 2000 (SRTM), 1990s (Landsat 5 image mosaic)
Ask any astronomer where the best stargazing site in Southern California is, and chances are they'll say Mt. Pinos. In this perspective view generated from SRTM elevation data the snow-capped peak is seen rising to an elevation of 2,692 meters (8,831 feet), in stark contrast to the flat agricultural fields of the San Joaquin valley seen in the foreground. Below the summit, but still well away from city lights, the Mt. Pinos parking lot at 2,468 meters (8,100 feet) is a popular viewing area for both amateur and professional astronomers and astro-photographers. For visualization purposes, topographic heights displayed in this image are exaggerated two times.The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.Distance to Horizon: 176 kilometers (109 miles) Location: 34.83 deg. North lat., 119.25 deg. West lon. View: Toward the Southwest Date Acquired: February 16, 2000 SRTM, December 14, 1984 Landsat
Ventura, California is one of this state's oldest cities. Officially known as San Buenaventura, it was established in 1782 with the founding of the Mission San Buenaventura, the ninth of the 21 Spanish missions founded in California. In this perspective view generated from SRTM elevation data, the city can be seen occupying the shore of the Pacific Ocean and the nearby foothills. Lake Casitas, a reservoir and popular recreation area, is the dark blue feature in the center of the image. Holding back the 313,000 megaliter (254,000 acre-feet) storage capacity of the reservoir and visible as a very bright feature foreground of the lake, is the Casitas Dam, a 102-meter(334-foot) Earth fill dam. The reservoir and dam were built between 1956 and 1959 for the Federal Bureau of Reclamation's Ventura River Project. In addition to recreational use, Lake Casitas provides irrigation, municipal and industrial water to urban and suburban areas in Ventura County. For visualization purposes, topographic heights displayed in this image are exaggerated two times.The elevation data used in this image was acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's land surface. To collect the 3-D SRTM data, engineers added a mast 60 meters (about 200 feet)long, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena.Distance to Horizon: 54.5 kilometers (33.8 miles) Location: 34.38 deg. North lat., 119.3 deg. West lon. View: Toward the North Date Acquired: February 16, 2000 SRTM, December 14, 1984 Landsat
A geological study of a 27,500 sq km area in the Los Andes region of northwestern Venezuela was performed which employed both X-band radar mosaics and computer processed Landsat images. The 3.12 cm wavelength radar data were collected with horizontal-horizontal polarization and 10 meter spatial resolution by an Aeroservices SAR system at an altitude of 12,000 meters. The radar images increased the number of observable suspected fractures by 27 percent over what could be mapped by LANDSAT alone, owing mostly to the cloud cover penetration capabilities of radar. The approximate eight fold greater spatial resolution of the radar images made possible the identification of shorter, narrower fractures than could be detected with LANDSAT data alone, resulting in the discovery of a low relief anticline that could not be observed in LANDSAT data. Exploration targets for petroleum, copper, and uranium were identified for further geophysical work.
Vincent, R. K.
An aerospace education activity is described which is suitable for grades 3-12. Students piece together several images from the Landsat satellite to make a mosaic of their state. From the mosaic clear acetate overlay maps can be made relating to such subjects as agriculture, geology, hydrology, or urban planning. (BB)
Marks, Steven K.
Official website for the Landsat Project. Landsat is concerned with the acquisition of images of the earth from space and is a joint endeavor of the United States Geological Survey and the National Aeronautics and Space Administration. The website contains information about the project as well as links to collections of images.
Survey, United S.
Landsat 7, the latest satellite in a series of earth remote sensing satellites, was launched into orbit on April 15, 1999. Of great importance to science, Landsat 7 gathers remotely sensed images of the land surface (and surrounding coastal regions) across the entire globe; using these images, researchers monitor "important small-scale processes on a global scale, such as the inter- and intra-annual cycles of vegetation growth; deforestation; agricultural land use; erosion and other forms of land degradation; snow accumulation and melt and the associated fresh-water reservoir replenishment; and urbanization." The Landsat 7 site provides general information on the satellite, including how images are taken and examples of satellite images. Additionally, several sections describe data (including acquisition), products (with links to examples of recent satellite images), and other applications.
This paper presents a methodology for measuring and improving the effectiveness of stepper overlay management on product wafers in the semiconductor industry. The research that supports this measurement approach encompasses over 12 fabs with over 30 technologies. Overlay performance, stepper deployment, stepper productivity and die yield loss due to overlay error were studied. To provide an objective measurement of a fab overlay methodology and performance, measurements were made of the overall overlay design rule compliance and distribution and of the overlay variance and distribution by stepper field location. Modeled data analysis was used to assess and validate the effectiveness of the stepper control methodology, sampling level and field/target locations. Balancing stepper productivity and overlay results is a problem in most fabs. An overlay 'opportunity box' is defined that allows a fab to explore overlay error ranges, lost stepper productivity, and product overlay design rule requirement by stepper deployment. Stepper deployment decision tend to be digital - 'engineering' or 'manufacturing' - quantification of die yield loss as a function of overlay error is usually required to make deployment changes. Several examples of die yield loss, as a function of overlay error and distribution, are presented. A brief introduction of the yield analysis technique used is provided.
Martin, Richard J.; Chen, Xuemei; Goldberger, Itzik
The author has identified the following significant results. Land cover overlays and maps produced from LANDSAT are providing information on existing land use and resources throughout the 208 study area. The overlays are being used to delineate drainage areas of a predominant land cover type. Information on cover type is also being combined with other pertinent data to develop estimates of sediment and nutrients flows from the drainage area. The LANDSAT inventory of present land cover together with population projects is providing a basis for developing maps of anticipated land use patterns required to evaluate impact on water quality which may result from these patterns. Overlays of forest types were useful for defining wildlife habitat and vegetational resources in the region. LANDSAT data and computer assisted interpretation was found to be a rapid cost effective procedure for inventorying land cover on a regional basis. The entire 208 inventory which include acquisition of ground truth, LANDSAT tapes, computer processing, and production of overlays and coded tapes was completed within a period of 2 months at a cost of about 0.6 cents per acre, a significant improvement in time and cost over conventional photointerpretation and mapping techniques.
Rogers, R. H. (principal investigator); Mckeon, J. B.; Reed, L. E.; Schmidt, N. F.; Schecter, R. N.
A Resilient Overlay Network (RON) is an architecture that allows distributed Internet applications to detect and recover from path outages and periods of degraded performance within several seconds, improving over today's wide-area routing protocols that take at least several minutes to recover. A RON is an application-layer overlay on top of the existing Internet routing substrate. The RON nodes monitor
David Andersen; Hari Balakrishnan; Frans Kaashoek; Robert Morris
Flight performances of LANDSAT 1 and LANDSAT 2 are evaluated. The in-flight systems discussed are: (1) power supplies, (2) attitude control, (3) command/clock, (4) telemetry, (5) orbit adjust, (6) electrical interface, (7) thermal, (8) tape recorders, (9) multispectral scanner, (10) data collection and (11) magnetic moment compensating assembly. Tables are presented for easy reference.
While Landsat data has been used to monitor primary production in range and pasture areas, such monitoring has generally been intended to track broad changes across multiple years. With an 8-day return time and 30m resolution, Landsat data can be used to assess intra-annual changes, even within rota...
In this publication we introduce a new metric for process robustness of overlay metrology in microelectronic manufacturing. By straightforward statistical analysis of overlay metrology measurements on an array of adjacent, nominally identical overlay targets the Overlay Mark Fidelity (OMF) can be estimated. We present the results of such measurements and analysis on various marks, which were patterned using a DUV scanner. The same reticle set was used to pattern wafers on different process layers and process conditions. By appropriate statistical analysis, the breakdown of the total OMF into a reticle-induced OMF component and a process induced OMF component was facilitated. We compare the OMF of traditional box-in-box overlay marks with that of new gratingbased overlay marks and show that in all cases the grating marks are superior. The reticle related OMF showed an improvement of 30 % when using the new grating-based overlay mark. Furthermore, in a series of wafers run through an STI-process with different Chemical Mechanical Polish (CMP) times, the random component of the OMF of the new grating-based overlay mark was observed to be 40% lower and 50% less sensitive to process variation compared with Box in Box marks. These two observations are interpreted as improved process robustness of the grating mark over box in box, specifically in terms of reduced site by site variations and reduced wafer to wafer variations as process conditions change over time. Overlay Mark Fidelity, as defined in this publication, is a source of overlay metrology uncertainty, which is statistically independent of the standard error contributors, i.e. precision, TIS variability, and tool to tool matching. Current overlay metrology budgeting practices do not take this into consideration when calculating total measurement uncertainty (TMU). It is proposed that this be reconsidered, given the tightness of overlay and overlay metrology budgets at the 70 nm design rule node and below.
Adel, Mike; Ghinovker, Mark; Poplawski, Jorge M.; Kassel, Elyakim; Izikson, Pavel; Pollentier, Ivan K.; Leray, Philippe; Laidler, David W.
The effect on LANDSAT data of a Sun angle correction, an intersatellite LANDSAT-2 and LANDSAT-3 data range adjustment, and the atmospheric correction algorithm was evaluated. Fourteen 1978 crop year LACIE sites were used as the site data set. The preprocessing techniques were applied to multispectral scanner channel data and transformed data were plotted and used to analyze the effectiveness of the preprocessing techniques. Ratio transformations effectively reduce the need for preprocessing techniques to be applied directly to the data. Subtractive transformations are more sensitive to Sun angle and atmospheric corrections than ratios. Preprocessing techniques, other than those applied at the Goddard Space Flight Center, should only be applied as an option of the user. While performed on LANDSAT data the study results are also applicable to meteorological satellite data.
Austin, W. W.
Report presents data derived from satellite images predicting pollution loads after rainfall. It explains method for converting Landsat images of Eastern United States into cover maps for Baltimore/five county region.
Castruccio, P.; Fowler, T.; Loats, H., Jr.
We have developed a method for calculating the statistical effects of spatial noise on the overlay measurement extracted from a given overlay target. The method has been applied to two kinds of overlay targets on three process layers, and the new metric, Target Noise, has been shown to correlate well to the random component of Overlay Mark Fidelity. A significant difference in terms of robustness has been observed between AIM targets and conventional Frame-in-Frame targets. The results fit well into the spatial noise hierarchy presented in this paper.
Seligson, Joel L.; Adel, Mike E.; Izikson, Pavel; Levinski, Vladimir; Yaffe, Dan
This final report summarizes three years of work characterizing the radiometry of the Landsat 4, 5 and 7 Thematic Mappers. It is divided into six sections that are representative of the major areas of effort: 1) Internal Calibrator Lamp Monitoring; 2) Vicarious Calibration; 3) Relative Gain Analysis; 4) Outgassing; 5) Landsat 4 Absolute Calibration; and 6) Landsat 5 Scene Invariant Analysis. Each section provides a summary overview of the work that has been performed at SDSU. Major results are highlighted. In several cases, references are given to publications that have developed from this work, Several team members contributed to this report: Tim Ruggles, Dave Aaron, Shriharsha Madhavan, Esad Micijevic, Cory Mettler, and Jim Dewald. At the end of the report is a summary section.
Viewgraphs are presented which highlight LANDSAT-D project status and ground segment; early access TM processing; LANDSAT-D data acquisition and availability; LANDSAT-D performance characterization; MSS pre-NOAA characterization; MSS radiometric sensor performance (spectral information, absolute calibration, and ground processing); MSS geometric sensor performance; and MSS geometric processing and calibration.
Landsat digital images are commonly analyzed by using the digital numbers for each pixel recorded on a computer-compatible magnetic tape. Although this procedure may be satisfactory when only a single, internally consistent image is used, the procedure may produce incorrect results if more than one image is used for analysis as in mosaics or temporal overlays. The digital numbers for each pixel should be converted to their dimensioned equivalents such as radiance, as measured at the satellite, in milliwatts per square centimetre per steradian, or reflectance.-from Author
Overlay networks are widely used to deploy functionality at edge nodes without changing network routers. Each node in an overlay network maintains pointers to a set of neighbor nodes. These pointers are used both to maintain the overlay and to implement application functionality, for example, to locate content stored by overlay nodes. If an attacker controls a large fraction of
Atul Singh; Miguel Castro; Peter Druschel; Antony I. T. Rowstron
1 Optimized Overlay Metrology Marks: Theory and Experiment M. Adel, M. Ghinovker, B. Golovanevsky a detailed analysis of overlay metrology mark and find the mapping between various properties of mark. Keywords Overlay metrology, overlay mark, Cramer-Rao lower bound, Fisher information matrix, box
Several studies were performed using LANDSAT-4 and -5 simultaneous overpath data 40608-15472 and 50014-15465 over Pensacola, FL. The overlap region of these two scenes was determined visually on the IAT and then sampled into 32 x 32 segments. The mean and standard deviation (SD) for each segment were calculated. In general, the plots of the means of LANDSAT-4 versus LANDSAT-5 lie on the diagonal line. Some of the data lie out of the diagonal line, which indicates a possible bidirectional observation effect occurs. In addition to editing the five FCL files on CALDUMP tapes into seven 1000 minor frame (MF). CAL files, program LEE.FOR was modified to use information from start of shutter obscuration extracted from program START.FOR to create seven 200 MF.CAL files that can be run through the current TRAPP program for TM sensor characterization. The location of start of shutter obscuration was determined for both LANDSAT-4 and -5.
Lee, Y. (principal investigator)
Landsat 5 image of the Mt. Redoubt area on March 26, 2009 at 1:07 PM AKDT. The false color image shows the large brown ash cloud extending over the Cook Inlet and the western Kenai peninsula (right sid of image). The image also shows a whiter steam and gas plume rising from the summit of Redoubt Vol...
The overall objective of a research effort at NASA's Goddard Space Flight Center is to develop and evaluate digital image processing techniques that will facilitate the assessment of the intensity and spatial distribution of forest insect damage in Northeastern U.S. forests using remotely sensed data from Landsats 1, 2 and C. Automated change detection techniques are presently being investigated as a method of isolating the areas of change in the forest canopy resulting from pest outbreaks. In order to follow the change detection approach, Landsat scene correction and overlay capabilities are utilized to provide multispectral/multitemporal image files of 'defoliation' and 'nondefoliation' forest stand conditions.
Williams, D. L.; Stauffer, M. L.
The transfer of remote sensing technology for the digital processing of LANDSAT data to state and local agencies in Georgia and other southeastern states is discussed. The project consists of a series of workshops, seminars, and demonstration efforts, and transfer of NASA-developed hardware concepts and computer software to state agencies. Throughout the multi-year effort, digital processing techniques have been emphasized classification algorithms. Software for LANDSAT data rectification and processing have been developed and/or transferred. A hardware system is available at EES (engineering experiment station) to allow user interactive processing of LANDSAT data. Seminars and workshops emphasize the digital approach to LANDSAT data utilization and the system improvements scheduled for LANDSATs C and D. Results of the project indicate a substantially increased awareness of the utility of digital LANDSAT processing techniques among the agencies contracted throughout the southeast. In Georgia, several agencies have jointly funded a program to map the entire state using digitally processed LANDSAT data.
Faust, N. L.; Spann, G. W.
For different CD metrologies like average CD from CD SEM and optical CD (OCD) from scatterometry, CD point-to-point R2 has been well adopted as the CD correlation index. For different overlay metrologies like image-based box-in-box overlay and scatterometry-based overlay, we propose the cosine similarity as the correlation index of overlay. The cosine similarity is a measure of similarity between two vectors of n dimensions by finding the cosine of the angle between them, often used to compare documents in text mining. It has been widely used in web and document search engines and can be used as the similarity index of overlay tool-to-tool matching and scanner tool-to-tool or day-to-day fingerprint. In this paper, we demonstrate that the cosine similarity has a very high sensitivity to the overly tool performance. We compared the similarities of three generations (A1, A2, A3) of the overlay tools of venders A and B and found that after target re-training and TIS correction on each tool A1 similarity to A3 can be improved from 0.9837 to 0.9951. Overlay point-to-point matching with A3 vs. A1 can be reduced from 4.8 to 2.1 nm. The tool precision similarities, i.e. tool self best similarity, for A1, A2, A3 and B are 0.9986, 0.9990, 0.9995, and 0.9994 respectively. From this table, we demonstrate that we can use old-generation overlay tool with suitable hardware maintenance, to match to the latest-generation overlay tool.
Ke, Chih-Ming; Kao, Ching-Pin; Wang, Yu-Hsi; Hu, Jimmy; Chang, Chen-Yu; Tsai, Ya-Jung; Yen, Anthony; Lin, Burn J.
The LANDSAT 4 thematic mapper sensor possesses approximately twice the spectral resolution, three times the spatial resolution, and four times the spectral sensitivity of the MSS sensor on earlier LANDSAT satellites. Spectral bands on the TM, particularly those at wavelengths of 1.6 and 2.2 micrometers are useful for: (1) distinguishing crops such as rice and soybeans; (2) surveying areas that are cultivated in strip crop fashion; (3) determining clay variations and abundances and rock classifications; and (4) differentiating nutrients and sediments found in coastal waters. The sensor can identify surface features 30 meters on a side, which roughly corresponds to a standard city block. Highway construction, land excavation, urban growth, and the health and extent of vegetation can be detected.
Learning objectives include: (1) developing a facility for applying conventional techniques of photointerpretation to small scale (satellite) imager; (2) promoting the ability to locate, identify, and interpret small natural and man made surface features in a LANDSAT image; (3) using supporting imagery, such as aerial and space photography, to conduct specific applications analyses; (4) learning to apply change detection techniques to recognize and explain transient and temporal events in individual or seasonal imagery; (5) producing photointerpretation maps that define major surface units, themes, or classes; (6) classifying or analyzing a scene for specific discipline applications in geology, agriculture, forestry, hyrology, coastal wetlands, and environmental pollution; and (7) evaluating both advantages and shortcomings in relying on the photointerpretive approach (rather than computer based analytical approach) for extracting information from LANDSAT data.
The U.S. Standard Catalog lists imagery of the continental U.S., Alaska and Hawaii acquired by Landsat 1 and 2 which has been processed and input to the data files during the referenced month. Data, such as date acquired, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found is also given.
Many computer algorithms for the analysis of Landsat data have a statistical basis which requires that the observations comprise independent samples. Four distinct methods are employed to show that this assumption commonly is not fulfilled for these data. Each leads to a similar conclusion; the data must be sampled no closer than every 10th pixel in order to yield independent estimators. The implications of this are illustrated with a simple example.
Craig, R. G.
The Global Land Information System (GLIS) lists Landsat multispectral scanner (MSS) and thematic mapper (TM) data available from the participating international ground stations shown below. These databases of the Landsat Ground Station Operations Working Group (LGSOWG) can be searched, but not ordered, using GLIS. To order Landsat scenes identified on the GLIS data search, contact the international ground station where those scenes are available, indicated by the second character of the Entity ID.
U.S. Geological Survey
Procedures to evaluate the accuracy of LANDSAT derived wildland cover classifications are described. The evaluation procedures include: (1) implementing a stratified random sample for obtaining unbiased verification data; (2) performing area by area comparisons between verification and LANDSAT data for both heterogeneous and homogeneous fields; (3) providing overall and individual classification accuracies with confidence limits; (4) displaying results within contingency tables for analysis of confusion between classes; and (5) quantifying the amount of information (bits/square kilometer) conveyed in the LANDSAT classification.
Toll, D. L.
Sample segments of ground-verified land cover data collected in conjunction with the USDA/ESS June Enumerative Survey were merged with LANDSAT data and served as a focus for unsupervised spectral class development and accuracy assessment. Multitemporal data sets were created from single-date LANDSAT MSS acquisitions from a nominal scene covering an eleven-county area in north central Missouri. Classification accuracies for the four land cover types predominant in the test site showed significant improvement in going from unitemporal to multitemporal data sets. Transformed LANDSAT data sets did not significantly improve classification accuracies. Regression estimators yielded mixed results for different land covers. Misregistration of two LANDSAT data sets by as much and one half pixels did not significantly alter overall classification accuracies. Existing algorithms for scene-to scene overlay proved adequate for multitemporal data analysis as long as statistical class development and accuracy assessment were restricted to field interior pixels.
Stoner, E. R.; May, G. A.; Kalcic, M. T. (principal investigators)
The extension of optical lithography to 2Xnm and beyond is often challenged by overlay control. With reduced overlay measurement error budget in the sub-nm range, conventional Total Measurement Uncertainty (TMU) data is no longer sufficient. Also there is no sufficient criterion in overlay accuracy. In recent years, numerous authors have reported new method of the accuracy of the overlay metrology: Through focus and through color. Still quantifying uncertainty in overlay measurement is most difficult work in overlay metrology. According to the ITRS roadmap, total overlay budget is getting tighter than former device node as a design rule shrink on each device node. Conventionally, the total overlay budget is defined as the square root of square sum of the following contributions: the scanner overlay performance, wafer process, metrology and mask registration. All components have been supplying sufficiently performance tool to each device nodes, delivering new scanner, new metrology tools, and new mask e-beam writers. Especially the scanner overlay performance was drastically decreased from 9nm in 8x node to 2.5nm in 3x node. The scanner overlay seems to reach the limitation the overlay performance after 3x nod. The importance of the wafer process overlay as a contribution of total wafer overlay became more important. In fact, the wafer process overlay was decreased by 3nm between DRAM 8x node and DRAM 3x node. We develop an analytical algorithm for overlay accuracy. And a concept of nondestructive method is proposed in this paper. For on product layer we discovered the layer has overlay inaccuracy. Also we use find out source of the overlay error though the new technique. In this paper, authors suggest an analytical algorithm for overlay accuracy. And a concept of non-destructive method is proposed in this paper. For on product layers, we discovered it has overlay inaccuracy. Also we use find out source of the overlay error though the new technique. Furthermore total overlay error data is decomposed into two parts: the systematic error and the random error. And we tried to show both error components characteristic, systematic error has a good correlation with residual error by scanner condition, whereas, random error has a good correlation with residual error as going process steps. Furthermore, we demonstrate the practical using case with proposed method that shows the working of the high order method through systematic error. Our results show that to characterize an overlay data that is suitable for use in advanced technology nodes requires much more than just evaluating the conventional metrology metrics of TIS and TMU.
Ham, Boo-Hyun; Yun, Sangho; Kwak, Min-Cheol; Ha, Soon Mok; Kim, Cheol-Hong; Nam, Suk-Woo
Three Seasat synthetic aperture radar (SAR) and three Landsat multispectral scanner subsystem (MSS) scenes of three areas of Alaska were analyzed for hydrological information. The areas were: the Dease Inlet in northern Alaska and its oriented or thaw lakes, the Ruth and Tokositna valley glaciers in south central Alaska, and the Malaspina piedmont glacier on Alaska's southern coast. Results for the first area showed that the location and identification of some older remnant lake basins were more easily determined in the registered data using an MSS/SAR overlay than in either SAR or MSS data alone. Separately, both SAR and MSS data were useful for determination of surging glaciers based on their distinctive medial moraines, and Landsat data were useful for locating the glacier firn zone. For the Malaspina Glacier scenes, the SAR data were useful for locating heavily crevassed ice beneath glacial debris, and Landsat provided data concerning the extent of the debris overlying the glacier.
Hall, D. K.; Ormsby, J. P.
The Landsat Data Continuity Mission (LDCM) is currently under development and is on schedule to launch the 8th satellite in the Landsat series in December of 2012. LDCM is a joint project between the National Aeronautics and Space Administration (NASA) and the United States Geological Survey (USGS). NASA is responsible for developing and launching the flight hardware and on-orbit commissioning and USGS is responsible for developing the ground system and operating the system onorbit after commissioning. Key components of the flight hardware are the Operational Land Imager (OLI), nearing completion by Ball Aerospace & Technologies Corp in Boulder, CO, the Thermal Infrared Sensor (TIRS), being built by NASA's Goddard Space Flight Center and the spacecraft, undergoing integration at Orbital Sciences Corp in Gilbert, Arizona. The launch vehicle will be an Atlas-5 with launch services provided by NASA's Kennedy Space Center. Key ground systems elements are the Mission Operations Element, being developed by the Hammers Corporation, and the Collection Activity Planning Element, Ground Network Element, and Data Processing and Archive System, being developed internally by the USGS Earth Resources Observations and Science (EROS) Center. The primary measurement goal of LDCM is to continue the global coverage of moderate spatial resolution imagery providing continuity with the existing Landsat record. The science goal for this imagery is to monitor land use and land cover, particularly as it relates to global climate change. Together the OLI and TIRS instruments on LDCM replace the ETM+ instrument on Landsat-7 with significant enhancements. The OLI is a pushbroom design instrument where the scanning mechanism of the ETM+ is effectively replaced by a long line of detectors. The OLI has 9 spectral bands with similar spatial resolution to ETM+: 7 of them similar to the reflective spectral bands on ETM+ and two new bands. The two new bands cover (1) the shorter wavelength blue part of the spectrum to help with coastal studies and aerosol analyses/atmospheric correction and (2) an atmospheric water absorption band, where the Earth surface is generally not visible, but Cirrus clouds are, to aid in cloud detection and screening. The radiometry of OLI benefits from improved SNR, dynamic range and quantization. OLI is undergoing system testing with a delivery scheduled for Spring 2011. The TIRS is also a pushbroom design and used QWIPS detectors that require cooling to 43K using a cryocooler. It.has two spectral bands, effectively splitting the ETM+ band 6 in half, that can be used as a split window to aid in atmospheric correction. It has nominally 100 m spatial resolution as opposed to the 60 m of Landsat-7 ETM+: TIRS has commenced integration and test, with a delivery to the spacecraft vendor scheduled for Winter 2011-2012. The Orbital spacecraft currently being integrated for LDCM will have improved capabilities for pointing over previous missions. These capabilities will allow the OLI and TIRS instruments to point off-nadir the equivalent of one WRS-2 path to increase the chances of coverage for high priority targets, particularly in the event of natural disasters. Also, the pointing capability will allow the calibration of the OLI using the sun (roughly weekly), the moon (monthly), stars (during commissioning) and the Earth (at 90 deg from normal orientation, a.k.a., side slither) quarterly. The solar calibration will be used for OLI absolute and relative calibration, the moon for trending the stability of the OLI response, the stars will be used for Line of Sight determination and the side slither will be an alternate OLI and relative gain determination methodology. The spacecraft is scheduled to begin integration with the OLI instrument in Summer 2011. The LDCM data processing and archive system (DPAS), located at USGS EROS, generates the products for distribution to users. Like Landsat-7 this includes an image assessment system for characrizing instrument performance and updating calibration parameters. Products will be generated tha
Markham, Brian; Irons, James; Dabney, Philip
As the first session of the 101st Congress draws to a close, chairman of the House Committee on Science, Space, and Technology George Brown is looking for a decision on the management, funding, and policy concerning the Landsat program. ``The development of a new policy framework for Landsat cannot be postponed any longer,'' he said at a November 26 hearing.His
The Landsat program is one of the longest running satellite programs for Earth observations from space. The program was initiated by the launch of Landsat 1 in 1972. Since then a series of six more Landsat satellites were launched and at least one of those satellites has been in operations at all times to continuously collect images of the global land surface. The Department of Interior (DOI) U.S. Geological Survey (USGS) preserves data collected by all of the Landsat satellites at their Earth Resources Observation and Science (EROS) Center in Sioux Falls, South Dakota. This 40-year data archive provides an unmatched record of the Earth's land surface that has undergone dramatic changes in recent decades due to the increasing pressure of a growing population and advancing technologies. EROS provides the ability for anyone to search the archive and order digital Landsat images over the internet for free. The Landsat data are a public resource for observing, characterizing, monitoring, trending, and predicting land use change over time providing an invaluable tool for those addressing the profound consequences of those changes to society. The most recent launch of a Landsat satellite occurred in 1999 when Landsat 7 was placed in orbit. While Landsat 7 remains in operation, the National Aeronautics and Space Administration (NASA) and the DOI/ USGS are building its successor satellite system currently called the Landsat Data Continuity Mission (LDCM). NASA has the lead for building and launching the satellite that will carry two Earth-viewing instruments, the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). The OLI will take images that measure the amount of sunlight reflected by the land surface at nine wavelengths of light with three of those wavelengths beyond the range of human vision. T1RS will collect coincident images that measure light emitted by the land surface as a function of surface temperature at two longer wavelengths well beyond the range of human vision. The DOI/USGS is developing the ground system that will command and control the LDCM satellite in orbit and manage the OLI and TIRS data transmitted by the satellite. DOI/USGS will thus operate the satellite and collect, archive, and distribute the image data as part of the EROS archive. DOI/USGS has committed to renaming LDCM as Landsat 8 following launch. By either name the satellite and its sensors will extend the 40-year archive with images sufficiently consistent with data from earlier Landsat satellites to allow multi-decadal, broad-area studies of our dynamic landscapes. The next Landsat satellite and ground system are on schedule for a January, 2013 launch.
Rons, James R.; Dwyer, John L.; Barsi, Julia A.
In 1982, NASA launched Landsat 4 as part of their on-going Landsat Program. Landsat 5 was launched in 1984, and Landsat 7, the current satellite acquiring images on a global scale, was launched in 1999. In the fall of 2000, NASA launched the Advanced Land Imager (ALI) as a part of the Earth Observat...
In cooperation with the International Landsat community, and through the Landsat Technical Working Group (LTWG), NOAA is assembling information about the status of the Worldwide Landsat Archive. During LTWG 9, member nations agreed to participate in a survey of International Landsat data holding and of their archive experiences with Landsat data. The goal of the effort was two-fold; one, to document the Landsat archive to date, and, two, to ensure that specific nations' experience with long-term Landsat archival problems were available to others. The survey requested details such as amount of data held, the format of the archive holdings by Spacecraft/Sensor, and acquisition years; the estimated costs to accumulated process, and replace the data (if necessary); the storage space required, and any member nation's plans that would establish the insurance of continuing quality. As a group, the LTWG nations are concerned about the characteristics and reliability of long-term magnetic media storage. Each nation's experience with older data retrieval is solicited in the survey. This information will allow nations to anticipate and plan for required changes to their archival holdings. Also solicited were reports of any upgrades to a nation's archival system that are currently planned and all results of attempts to reduce archive holdings including methodology, current status, and the planned access rates and product support that are anticipated for responding to future archival usage.
Warriner, Howard W.
The author has identified the following significant results. Two sets of urban test sites, one with 35 cities and one with 70 cities, were selected in the State, Sao Paulo. A high degree of colinearity (0.96) was found between urban and areal measurements taken from aerial photographs and LANDSAT MSS imagery. High coefficients were observed when census data were regressed against aerial information (0.95) and LANDSAT data (0.92). The validity of population estimations was tested by regressing three urban variables, against three classes of cities. Results supported the effectiveness of LANDSAT to estimate large city populations with diminishing effectiveness as urban areas decrease in size.
Dejesusparada, N. (principal investigator); Foresti, C.
This paper presents relationships among Landsat MSS bands and selected transformations of them, with emphasis on the Tasseled-Cap Transformation and its Brightness, Greenness variables. It also discusses relationships between reflectance measurements made in the Landsat spectral bands and actual Landsat data. Agronomically oriented analyses of reflectance measurements of wheat throughout a growing season are presented, with a comparison of various green measures, correlation with crop development stage, and examination of the effects of moisture stress. The final example addresses the use of transformed variables in a newly developed approach to forestry change detection.
Malila, W. A.; Lambeck, P. F.; Crist, E. P.; Jackson, R. D.; Pinter, P. J., Jr.
Landsats 4 and 5, the latest in the series of unmanned earth observation satellites, are used as the space platform for two remote sensing, mechanical scanning instruments: the multispectral scanner (MSS) and the recently developed thematic mapper (TM). The primary objective of the experimental portion of the Landsat 4 and 5 missions is to assess the capability of the TM to provide improved information relative to the MSS.The higher spatial resolution of the TM over the MSS requires a higher degree of flight segment attitude stability than the earlier Landsats; therefore, a more stable, low-orbit space platform must be provided. This paper describes the orbital, electrical, mechanical, and thermal characteristics of Landsat 4 and 5 flight segment with special emphasis on the TM and MSS interfaces. Also described are flight segment disturbances caused by the TM and MSS scanning mirrors, motion from the Tracking and Data Relay Satellite (TDRS) antenna, solar array, and the attitude control system (ACS).
Schulman, J. R.
The current status of the Brazilian LANDSAT facilities is described and main accomplishments are outlined. Receiving, recording, and processing substations and data distribution centers are discussed. Examples of the preliminary TM product produced by the Brazilian station are given.
Parada, N. D. J. (principal investigator); Barbosa, M. N.; Escada, J. B., Jr.
This collection of visualizations was made from Landsat imagery. Many of these visualizations are designed to show changes in our environment through time. Subjects include glacial retreat, urban growth, landforms and coastlines, floods, fires, deforestation, volcanism, and others.
The double patterning (DPT) process is foreseen by the industry to be the main solution for the 32 nm technology node and even beyond. Meanwhile process compatibility has to be maintained and the performance of overlay metrology has to improve. To achieve this for Image Based Overlay (IBO), usually the optics of overlay tools are improved. It was also demonstrated that these requirements are achievable with a Diffraction Based Overlay (DBO) technique named SCOLTM . In addition, we believe that overlay measurements with respect to a reference grid are required to achieve the required overlay control . This induces at least a three-fold increase in the number of measurements (2 for double patterned layers to the reference grid and 1 between the double patterned layers). The requirements of process compatibility, enhanced performance and large number of measurements make the choice of overlay metrology for DPT very challenging. In this work we use different flavors of the standard overlay metrology technique (IBO) as well as the new technique (SCOL) to address these three requirements. The compatibility of the corresponding overlay targets with double patterning processes (Litho-Etch-Litho-Etch (LELE); Litho-Freeze-Litho-Etch (LFLE), Spacer defined) is tested. The process impact on different target types is discussed (CD bias LELE, Contrast for LFLE). We compare the standard imaging overlay metrology with non-standard imaging techniques dedicated to double patterning processes (multilayer imaging targets allowing one overlay target instead of three, very small imaging targets). In addition to standard designs already discussed , we investigate SCOL target designs specific to double patterning processes. The feedback to the scanner is determined using the different techniques. The final overlay results obtained are compared accordingly. We conclude with the pros and cons of each technique and suggest the optimal metrology strategy for overlay control in double patterning processes.
Leray, Philippe; Cheng, Shaunee; Laidler, David; Kandel, Daniel; Adel, Mike; Dinu, Berta; Polli, Marco; Vasconi, Mauro; Salski, Bartlomiej
Aspen, conifer and mixed aspen/conifer forests were mapped for a 15-quadrangle study area in the Utah-Idaho Bear River Range using LANDSAT multispectral scanner data. Digital classification and statistical analysis of LANDSAT data allowed the identification of six groups of signatures which reflect different types of aspen/conifer forest mixing. Photo interpretations of the print symbols suggest that such classes are indicative of mid to late seral aspen forests. Digital print map overlays and acreage calculations were prepared for the study area quadrangles. Further field verification is needed to acquire additional information about the nature of the forests. Single date LANDSAT analysis should be a cost effective means to index aspen forests which are at least in the mid seral phase of conifer invasion. Since aspen canopies tend to obscure understory conifers for early seral forests, a second date analysis, using data taken when aspens are leafless, could provide information about early seral aspen forests.
Jaynes, R. A.; Merola, J. A.
The integrated LANDSAT-D systems operation plan is presented and discussed with respect to functional elements, personnel, and procedures. Specifically, a review of the LANDSAT-D program, mission requirements and management, and flight operations is given.
The orbit adjust maneuvers performed to raise the LANDSAT 5 spacecraft to mission altitude, synchronize it with the required groundtrack, and properly phase the spacecraft with LANDSAT-4 to provide an 8 day full Earth coverage cycle are described. Maneuver planning and evaluation procedures, data and analysis results for all maneuvers performed to date, the frozen orbit concept, and the phasing requirement between LANDSAT-4 and LANDSAT-5 are also examined.
Hassett, P. J.; Johnson, R. L.
This viewer lets students see near real-time images from the Landsat 5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper Plus (ETM+). When a Landsat satellite passes within range of the ground station at the USGS Center for Earth Resources Observation and Science (EROS), image data are downlinked and displayed in near-real time. When no satellites are within range, the most recent pass is displayed. By viewing the moving display, students can monitor changes in the Earth's surface. An index map and information display shows the path of the satellite, indicates which satellite is currently providing the imagery, and gives the acquisition date and time. A help page and frequently-asked-questions feature are provided to explain how to use the site.
Map characteristics of the Landsat mosaics developed at JPL are considered. Procedures for digital mosaicking of Landsat frames to standard map projections were used to mosaic at full resolution ten scenes over the California desert region and twenty-one scenes over Arizona. The procedures are analyzed for horizontal positioning error (global and local) and the potential for classification error associated with the adjustment of brightness of Z values between frames; the use of this technology for the mapping of extensive features is discussed. Mosaicking facilities, techniques, mapping accuracy, and thematic mapping characteristics are described. A comparative analysis of Landsat mosaicking technology developed at Goddard Space Flight Center, IBM Gaithersburg, and USGS Flagstaff is made, and suggestions are given for algorithm development to improve systems capacity and ability to handle a variety of cases.
Zobrist, A. L.; Bryant, N. A.
A variety of features characteristic of rotational landslides may be identified on Landsat imagery. These include tonal mottling, tonal banding, major and secondary scarps, and ponds. Pseudostereoscopic viewing of 9 by 9 in. transparencies was useful for the detailed identification of landslides, whereas 1:250,000 prints enlarged from 70 mm negatives were most suitable for regional analysis. Band 7 is the most useful band for landslide recognition, due to accentuation of ponds and shadows. Examination of both bands 7 and 5, including vegetation information, was found to be most suitable. Although, given optimum terrain conditions, some landslides in Colorado may be recognized, many smaller landslides are not identifiable. Consequently, Landsat is not recommended for detailed regional mapping, or for use in areas similar to Colorado, where alternative (aircraft) imagery is available. However, Landsat may prove useful for preliminary landslide mapping in relatively unknown areas.
Sauchyn, D. J.; Trench, N. R.
storage systems to resist state-level Internet censorship, construct a system that fulfills thoseCensorship resistant overlay publishing Technical Report Department of Computer Science-027 Censorship resistant overlay publishing Eugene Y. Vasserman, Victor Heorhiadi, Yongdae Kim, and Nicholas J
Minnesota, University of
Optimal Rate Allocation in Overlay Content Distribution Chuan Wu and Baochun Li Department. This paper addresses the optimal rate allocation problem in overlay content distribution for efficient, these scenarios reflect the contrast between elastic and streaming content distribution, with either per
Overcast is an application-level multicasting system that can be incrementally deployed using today's Internet infrastructure. These properties stem from Overcast's implementation as an overlay network. An overlay network consists of a collection of nodes placed at strategic locations in an existing network fabric. These nodes implement a network abstrac- tion on top of the network provided by the under- lying
John Jannotti; David K. Gifford; Kirk L. Johnson; M. Frans Kaashoek; James W. O'Toole Jr.
A digitized multispectral image, such as LANDSAT data, is composed of numerous four dimensional vectors, which quantitatively describe the ground scene from which the data are acquired. The statistics of unique vectors that occur in LANDSAT imagery are studied to determine if that information can provide some guidance on reducing image processing costs. A second purpose of this report is to investigate how the vector statistics are changed by various types of image processing techniques and determine if that information can be useful in choosing one processing approach over another.
Jayroe, R. R., Jr.; Underwood, D.
The National Aeronautics and Space Administration (NASA) launched the Landsat Data Continuity Mission (LDCM) on February 11, 2013 placing the eighth satellite in the Landsat series in orbit. The U.S. Geological Survey assumed responsibility for operations following a 100-day commissioning period and promptly renamed the satellite Landsat 8 on May 30, 2013. The satellite and its sensor payload, the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS), have performed magnificently since launch. The OLI signal-to-noise performance, for example, exceeds specifications by factors greater than 1.5 for every spectral band. TIRS is providing data with noise-equivalent-changes-in-temperature of less then 0.1 Kelvin compared to requirements of 0.4 Kelvin for its two thermal bands. The geometry of the images is also excellent with band-to-band registration accuracy, for example, of no more than 3.0 m for the OLI bands. The Landsat 8 level 1 data products are orthorectified and registered to the Universal Transverse Mercator cartographic projection with an uncertainty less than 5 m for OLI 30 m pixels and less than 35 m for TIRS 100 m pixels. The only exception to full specification compliance lies with the TIRS radiometric calibration. Discrepancies have been noted between calibrated Landsat 8 thermal data, TIRS Bands 10 and 11, and surface water temperature measurements collected to validate thermal band calibration. Surface water temperatures derived from TIRS data, after correction for atmospheric transmission and emissivity, are warmer than measured surface water temperatures by 2 K or more. This indicates a possible bias or other error in TIRS calibration that places the calibration uncertainty beyond the specified performance of 2 percent. Analysts continue to compare TIRS data to surface temperature measurements to discover the source of the discrepancy. Updates to TIRS calibration coefficients will be incorporated into Landsat 8 data processing as soon as the discrepancy is sufficiently understood. This presentation will report the current performance of Landsat 8 and will discuss the impact of the performance on Landsat data analyses and applications.
Irons, J. R.
The LANDSAT satellite is an effective tool in meeting the natural resources data requirements of state and federal legislation. The availability of data from the satellite is beginning to have an impact on state legislature activities. An overview of the history, operation, and data analysis techniques, is presented as well as a discussion of the advantages and limitations of this method of remote sensing. Applications are discussed in the areas of (1) land resource planning and management; (2) coastal zone management; (3) agriculture; (4) forestry; (5) routing and siting; (6) environmental monitoring; and (7) geological exploration. National and state sources from which information about LANDSAT technology is available are listed.
Analytical and test results on the use of adaptive processing on LANDSAT data are presented. The Kalman filter was used as a framework to contain different adapting techniques. When LANDSAT MSS data were used all of the modifications made to the Kalman filter performed the functions for which they were designed. It was found that adaptive processing could provide compensation for incorrect signature means, within limits. However, if the data were such that poor classification accuracy would be obtained when the correct means were used, then adaptive processing would not improve the accuracy and might well lower it even further.
Crane, R. B.; Reyer, J. F.
The Landsat Data Continuity Mission (LDCM) is the next in the series of Landsat satellite missions and is tasked with the objective of delivering data acquired by the Operational Land Imager (OLI). The OLI instrument will provide data continuity to over 30 years of global multispectral data collected by the Landsat series of satellites. The U.S. Geological Survey Earth Resources Observation and Science (USGS EROS) Center has responsibility for the development and operation of the LDCM ground system. One of the mission objectives of the LDCM is to distribute OLI data products electronically over the Internet to the general public on a nondiscriminatory basis and at no cost. To ensure the user community and general public can easily access LDCM data from multiple clients, the User Portal Element (UPE) of the LDCM ground system will use OGC standards and services such as Keyhole Markup Language (KML), Web Map Service (WMS), Web Coverage Service (WCS), and Geographic encoding of Really Simple Syndication (GeoRSS) feeds for both access to and delivery of LDCM products. The USGS has developed and tested the capabilities of several successful UPE prototypes for delivery of Landsat metadata, full resolution browse, and orthorectified (L1T) products from clients such as Google Earth, Google Maps, ESRI ArcGIS Explorer, and Microsoft's Virtual Earth. Prototyping efforts included the following services: using virtual globes to search the historical Landsat archive by dynamic generation of KML; notification of and access to new Landsat acquisitions and L1T downloads from GeoRSS feeds; Google indexing of KML files containing links to full resolution browse and data downloads; WMS delivery of reduced resolution browse, full resolution browse, and cloud mask overlays; and custom data downloads using WCS clients. These various prototypes will be demonstrated and LDCM service implementation plans will be discussed during this session.
Neiers, M.; Dwyer, J.; Neiers, S.
A flight performance analysis of the LANDSAT-1 spacecraft is presented, and some of the following were examined: (1) orbital parameters; (2) power subsystem; (3) attitude control subsystem; (4) command/clock subsystem; (5) narrowband tape recorders; and (6) magnetic moment compensating assembly.
The Landsat 7 Science Data Processing System, developed by NASA for the Landsat 7 Project, provides the science data handling infrastructure used at the Earth Resources Observation Systems (EROS) Data Center (EDC) Landsat Data Handling Facility (DHF) of the United States Department of Interior, United States Geological Survey (USGS) located in Sioux Falls, South Dakota. This paper presents an overview of the Landsat 7 Science Data Processing System and details of the design, architecture, concept of operation, and management aspects of systems used in the processing of the Landsat 7 Science Data.
Schweiss, Robert J.; Daniel, Nathaniel E.; Derrick, Deborah K.
As of writing in mid-2010, both Landsat-5 and -7 continue to function, with sufficient fuel to enable data collection until the launch of the Landsat Data Continuity Mission (LDCM) scheduled for December of 2012. Failure of one or both of Landsat-5 or -7 may result in a lack of Landsat data for a period of time until the 2012 launch. Although the potential risk of a component failure increases the longer the sensor's design life is exceeded, the possible gap in Landsat data acquisition is reduced with each passing day and the risk of Landsat imagery being unavailable diminishes for all except a handful of applications that are particularly data demanding. Advances in Landsat data compositing and fusion are providing opportunities to address issues associated with Landsat-7 SLC-off imagery and to mitigate a potential acquisition gap through the integration of imagery from different sensors. The latter will likely also provide short-term, regional solutions to application-specific needs for the continuity of Landsat-like observations. Our goal in this communication is not to minimize the community's concerns regarding a gap in Landsat observations, but rather to clarify how the current situation has evolved and provide an up-to-date understanding of the circumstances, implications, and mitigation options related to a potential gap in the Landsat data record. ?? 2010.
Wulder, M.A.; White, J.C.; Masek, J.G.; Dwyer, J.; Roy, D.P.
The CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol for Interplanetary Overlay Network (CFDP-ION) is an implementation of CFDP that uses IO' s DTN (delay tolerant networking) implementation as its UT (unit-data transfer) layer. Because the DTN protocols effect automatic, reliable transmission via multiple relays, CFDP-ION need only satisfy the requirements for Class 1 ("unacknowledged") CFDP. This keeps the implementation small, but without loss of capability. This innovation minimizes processing resources by using zero-copy objects for file data transmission. It runs without modification in VxWorks, Linux, Solaris, and OS/X. As such, this innovation can be used without modification in both flight and ground systems. Integration with DTN enables the CFDP implementation itself to be very simple; therefore, very small. Use of ION infrastructure minimizes consumption of storage and processing resources while maximizing safety.
Burleigh, Scott C.
In this publication, the contributors to in-field overlay metrology uncertainty have been parsed and quantified in a specific case study. Particular focus is placed on the unmodeled systematics, i.e. the components which contribute to residuals in a linear model after removal of random errors. These are the contributors which are often the most challenging to quantify and are suspected to be significant in the model residuals. The results show that even in a relatively "clean" front end process, the unmodeled systematics are the dominant residual contributor, accounting for 60 to 70% of the variance. Given the above results, new sampling and modeling methods are proposed which have the potential to improve the accuracy of modeled correctibles and lot dispositioning parameters.
Frommer, Aviv; Kassel, Elyakim; Izikson, Pavel; Adel, Mike; Leray, Philippe; Schulz, Bernd
The LANDSAT-1 spacecraft was launched from the Western Test Range on 23 July 1972, at 18:08:06.508Z. The launch and orbital injection phase of the space flight was nominal and deployment of the spacecraft followed predictions. Orbital operations of the spacecraft and payload subsystems were satisfactory through Orbit 147, after which an internal short circuit disabled one of the Wideband Video Tape Recorders (WBVTR-2). Operations resumed until Orbit 196, when the Return Beam Vidicon failed to respond when commanded off. The RBV was commanded off via alternate commands. LANDSAT-1 continued to perform its imaging mission with the Multispectral Scanner and the remaining Wideband Video Tape Recorder providing image data.
It could be argued that the biggest challenge of the 32 nm half pitch node is the production implementation of double patterning lithography. Within the framework of this broad domain, a specific challenge which has been highlighted is overlay control due to the sharing between two exposures the overlay control allocation of a single patterning step. The models used in the literature to support this assertion are reviewed and compared with recent results. An analysis of the implications for overlay metrology performance and cost of ownership is presented and compared with actual capabilities currently available with both imaging and scatterometry sensor technology. Technology matching between imaging and scatterometry emerges as a requirement to enable combined imaging scatterometry overlay control use cases.
Overlay metrology has become a cornerstone requirement which enables modern lithographic patterning. The mantra of metrology engineers in the litho cell and tool vendors alike has traditionally been TMU — Total Measurement Uncertainty — a metric which combines all sources of metrology tool related uncertainty. Although relentless TMU reduction is essential, it is certainly not a sufficient condition to meet the overlay control needs for the 32 nm node and below. Many other "on wafer" contributors must be factored into the uncertainty equation. A wider scope in the definition of the overlay metrology process is required which views it as part of the greater IC manufacturing process. Current and emerging overlay metrology industry practices will be reviewed in light of the increasing complexity associated with the interactions between metrology tool, target design and the sampling plan.
The solidification behavior (microsegregation, secondary phase formation, and solidification temperature range) of an Alloy 625 weld overlay deposited on 2.25Cr - 1Mo steel by gas metal arc welding was investigated by light and electron optical microscopy, electron microprobe, and differential thermal analysis techniques. The overlay deposit was found to terminate solidification at ≈ 1216 °C by a gamma\\/Laves eutectic-type reaction.
J. N. Dupont
The solidification behavior (microsegregation, secondary phase formation, and solidification temperature range) of an Alloy\\u000a 625 weld overlay deposited on 2.25Cr - 1Mo steel by gas metal arc welding was investigated by light and electron optical microscopy,\\u000a electron microprobe, and differential thermal analysis techniques. The overlay deposit was found to terminate solidification\\u000a at ? 1216 C by a?\\/Laves eutectic-type reaction. The
J. N. DuPont
The feasibility of automated classification for lithologic mapping with LANDSAT digital data was evaluated using three classification algorithms. The two supervised algorithms analyzed, a linear discriminant analysis algorithm and a hybrid algorithm which incorporated the Parallelepiped algorithm and the Bayesian maximum likelihood function, were comparable in terms of accuracy; however, classification was only 50 per cent accurate. The linear discriminant analysis algorithm was three times as efficient as the hybrid approach. The unsupervised classification technique, which incorporated the CLUS algorithm, delineated the major lithologic boundaries and, in general, correctly classified the most prominent geologic units. The unsupervised algorithm was not as efficient nor as accurate as the supervised algorithms. Analysis of spectral data for the lithologic units in the 0.4 to 2.5 microns region indicated that a greater separability of the spectral signatures could be obtained using wavelength bands outside the region sensed by LANDSAT.
Siegal, B. S.; Abrams, M. J.
The current status of the Brazilian LANDSAT facilities operated by Instituto de Pesquisas Espaciais (INPE) and the results achieved during the period from October 1, 1984 to August 31, 1985 are presented. INPE's Receiving Station at Cuiaba, MT, operates normally the two tracking and receiving systems it has installed, the old one (1973) for Band S and the new one (February 1983) for dual S- and X-band. Both MSS and TM recording capabilities are functional. Support to the NASA Backup Plan for MSS data also remains active. Routine recordings are being made for LANDSAT-5 only, for both MSS and TM. Originally, MSS was recorded over the full acquisition range. However, since December, 1984, due to further reduction of operational expenses, both instruments are being recorded over Brazilian territory only.
Debarrosaguirre, J. L.
This report describes a study examining the effects of overlaying a veil of spots on the letters in a central rapid serial visual presentation stream. Observers identified two target letters (T1 and T2, respectively) embedded in a stream of distractor letters printed in a different color. In Experiment 1, the attentional blink (AB) diminished when a different overlay veiled each letter, such that the spots appeared to move as the letters changed. Experiment 2 concerned whether the performance enhancement occurred because the overlay hampered processing of the lag 1 distractor, thus weakening the distractor's interference with T1. Experiment 3 focused on how changing the overlay at or around T1 affected the AB. The attention disengagement hypothesis was proposed to explain the common theme in the results-that performance was only enhanced when different overlays were applied to the T1 and lag 1 frames. The claim is that the AB reflects a failure of prompt attentional disengagement from T1, which, in turn, delays reengagement when T2 appears shortly thereafter. When T1's disappearance is accompanied by an overlay change, the perceptual system gets an additional cue signaling that the visual scene has changed, thereby inducing attentional disengagement. Apart from facilitating prompt reengagement at the next target, earlier disengagement also improves target recovery by excluding features of the trailing item, likely to be a distractor, from working memory. PMID:25245077
Chua, Fook K
The trophic status of a number of inland lakes in Wisconsin has been assessed. The feasibility of using both photographic and digital representations of Landsat imagery was investigated during the lake classification project. The result of the investigation has been a semi-automatic data acquisition and handling system which, in conjunction with an analytical categorization scheme, can be used to classify all the significant lakes in the state.
Scarpace, F. L.; Fisher, L. T.; Holmquist, K. W.
A digital elevation model (DEM) developed from Landsat TM images of a rugged terrain area in north Georgia by automated stereocorrelation techniques yielded an rms error (z), RMSE(z), value of + or - 42 m. Based on the B/H ratio of 0.18 for the Landsat data, this Z-error corresponds to a planimetric correlation accuracy of about + or - 0.3 pixels, confirming that precise correlation can be achieved with operational satellite data. Contours at a 100-m interval interpolated from the DEM show a deviation of + or - 33 m from reference contours obtained from existing 1:24,000-scale maps. The 28.5-m pixel resolution and the weak B/H ratio impose limitations on the accuracy that can be achieved with Landsat TM data. However, it is anticipated that RMSE(z) values of + or - 10 m or less can be achieved with SPOT-1 panchromatic stereo images of 10-m resolution recorded at B/H ratios of 0.5 to 1.0. DEMs generated by stereocorrelation techniques can be used to create orthoimages, perspective views, and topographic map products.
Ehlers, Manfred; Welch, R.
With the successful launch of Landsat-1 a series of rangeland investigations was begun by Texas A & M University. This series has been continuous and has evolved from the initial research phase of examining what Landsat could do into the present stage of evaluating the transfer of information and technology to the agri-business community. The discussion presented here consists of three parts: a brief history of rangeland Landsat work; present research efforts and results; and the present information transfer investigation.
Harlan, J. C.; Haas, R. H.; Boyd, W. E.; Deering, D. W.
The original configuration of the GSFC data acquisition, preprocessing, and transmission subsystem, designed to provide LANDSAT data inputs to the LACIE system at JSC, is described. Enhancements made to support LANDSAT -2, and modifications for LANDSAT -3 are discussed. Registration performance throughout the 3 year period of LACIE operations satisfied the 1 pixel root-mean-square requirements established in 1974, with more than two of every three attempts at data registration proving successful, notwithstanding cosmetic faults or content inadequacies to which the process is inherently susceptible. The cloud/snow rejection rate experienced throughout the last 3 years has approached 50%, as expected in most LANDSAT data use situations.
Horn, T. N.; Brown, L. E.; Anonsen, W. H. (principal investigators)
The erosion of materials by the impact of solid particles has received increasing attention during the past twenty years. Recently, research has been initiated with the event of advanced coal conversion processes in which erosion plays an important role. The resulting damage, termed Solid Particle Erosion (SPE), is of concern primarily because of the significantly increased operating costs which result in material failures. Reduced power plant efficiency due to solid particle erosion of boiler tubes and waterfalls has led to various methods to combat SPE. One method is to apply coatings to the components subjected to erosive environments. Protective weld overlay coatings are particularly advantageous in terms of coating quality. The weld overlay coatings are essentially immune to spallation due to a strong metallurgical bond with the substrate material. By using powder mixtures, multiple alloys can be mixed in order to achieve the best performance in an erosive environment. However, a review of the literature revealed a lack of information on weld overlay coating performance in erosive environments which makes the selection of weld overlay alloys a difficult task. The objective of this project is to determine the effects of weld overlay coating composition and microstructure on erosion resistance. These results will lead to a better understanding of erosion mitigation in CFB's.
The solidification behavior (microsegregation, secondary phase formation, and solidification temperature range) of an Alloy 625 weld overlay deposited on 2.25Cr - 1Mo steel by gas metal arc welding was investigated by light and electron optical microscopy, electron microprobe, and differential thermal analysis techniques. The overlay deposit was found to terminate solidification at ? 1216 °C by a ?/Laves eutectic-type reaction. The Laves phase was highly enriched in Nb, Mo, and Si. The solidification reaction and microsegregation potential of major alloying elements in the overlay deposit are compared to other Nb-bearing Ni base alloys and found to be very similar to those for Alloy 718. Solidification cracks observed in the overlay were attributed to the wide solidification temperature range (?170 °C) and formation of interdendritic ( ?+Laves) constituent. Reasonable agreement is obtained between the calculated and measured volume percent ( ?+Laves) constituent with the Scheil equation by treating the overlay system as a simple ?-Nb “binary” and using an experimentally determined k Nb value from electron microprobe data.
Dupont, J. N.
Viewing Earth from space, the Landsat 7 satellite takes images of the Earth, which allows us to look at land changes such as; urban growth, deforestation, and overall changes in the Earth itself. Here is a Landsat 7 image of Tampa, Florida
This educational brief presents a discussion of how the Landsat project has been able to provide data on environmental changes and potential problems. Topics include a short history of the project, an overview of the sorts of environmental issues Landsat satellites are able to "see" from space, and a brief description of ground truthing and how it supports remotely sensed data.
This guide was produced for science writers and the media and profiles several Landsat 7 research projects, and provides background and contact information. Landsat 7 is advancing several areas of Earth science, mass balance, cloud and aerosol heights, as well as land topography and vegetation characteristics. including monitoring croplands and mapping Antarctic ice streams.
Portions of the LANDSAT-D systems operation plan are presented. An overview of the data processing operations, logistics and other operations support, prelaunch and post-launch activities, thematic mapper operations during the scrounge period, and LANDSAT-D performance evaluation is given.
The overlay control budget for the 32nm technology node will be 5.7nm according to the ITRS. The overlay metrology budget is typically 1/10 of the overlay control budget resulting in overlay metrology total measurement uncertainty (TMU) requirements of 0.57nm for the most challenging use cases of the 32nm node. The current state of the art imaging overlay metrology technology does not meet this strict requirement, and further technology development is required to bring it to this level. In this work we present results of a study of an alternative technology for overlay metrology - Differential signal scatterometry overlay (SCOL). Theoretical considerations show that overlay technology based on differential signal scatterometry has inherent advantages, which will allow it to achieve the 32nm technology node requirements and go beyond it. We present results of simulations of the expected accuracy associated with a variety of scatterometry overlay target designs. We also present our first experimental results of scatterometry overlay measurements, comparing this technology with the standard imaging overlay metrology technology. In particular, we present performance results (precision and tool induced shift) and address the issue of accuracy of scatterometry overlay. We show that with the appropriate target design and algorithms scatterometry overlay achieves the accuracy required for future technology nodes.
Kandel, Daniel; Adel, Mike; Dinu, Berta; Golovanevsky, Boris; Izikson, Pavel; Levinski, Vladimir; Vakshtein, Irina; Leray, Philippe; Vasconi, Mauro; Salski, Bartlomiej
Landsat-4 satellite Thematic Mapper (TM) and multispectral scanner (MSS) data have been analyzed in order to ascertain data quality and information content. Geometric evaluations have tested band-to-band registration accuracy, and the TM's overall system resolution was evaluated for the case of image objects with high contrast, sharp edge responses. The information content evaluation employed clustering, principal components, and the transformed divergence separability measured on data from Iowa and Chicago, Illinois. The MSS classification analysis compared MSS and TM information contents for a large number of science classes.
Anuta, P.; Bartolucci, L.; Dean, E.; Lozano, F.; Malaret, E.; Mcgillem, C.; Valdes, J.; Valenzuela, C.
The purpose of this paper is to present a new global patent map that represents all technological categories, and a method to locate patent data of individual organizations and technological fields on the global map. This second patent overlay map technique is shown to be of potential interest to support competitive intelligence and policy decision-making. The global patent map is based on similarities in citing-to-cited relationships between categories of the International Patent Classification (IPC) of European Patent Office (EPO) patents from 2000 to 2006. This patent dataset, extracted from PatStat database, represents more than 760,000 patent records in more than 400 IPC categories. To illustrate the kind of analytical support offered by this approach, the paper shows the overlay of nanotechnology-related patenting activities of two companies and two different nanotechnology subfields on to the global patent map. The exercise shows the potential of patent overlay maps to visualize technological areas and...
Kay, Luciano; Youtie, Jan; Porter, Alan L; Rafols, Ismael
A literature review was made. In spite of similarities between abrasive wear and solid particle erosion, weld overlay hardfacing alloys that exhibit high abrasion resistance may not necessarily have good erosion resistance. The performance of weld overlay hardfacing alloys in erosive environments has not been studied in detail. It is believed that primary-solidified hard phases such as carbides and intermetallic compounds have a strong influence on erosion resistance of weld overlay hardfacing alloys. However, relationships between size, shape, and volume fraction of hard phases in a hardfacing alloys and erosion resistance were not established. Almost all hardfacing alloys can be separated into two major groups based upon chemical compositions of the primary solidified hard phases: (a) carbide hardening alloys (Co-base/carbide, WC-Co and some Fe base superalloys); and (b) intermetallic hardening alloys (Ni-base alloys, austenitic steels, iron-aluminides).
Levin, B.; DuPont, J.N.; Marder, A.R.
LANDSAT digital multispectral scanner data, in conjunction with supporting ground truth, were investigated to determine their utility in delineation of urban-rural boundaries. The digital data for the metropolitan areas of Washington, D. C.; Austin, Texas; and Seattle, Washingtion; were processed using an interactive image processing system. Processing focused on identification of major land cover types typical of the zone of transition from urban to rural landscape, and definition of their spectral signatures. Census tract boundaries were input into the interactive image processing system along with the LANDSAT single and overlayed multiple date MSS data. Results of this investigation indicate that satellite collected information has a practical application to the problem of urban area delineation and to change detection.
Christenson, J. W.; Lachowski, H. M.
SUMMARY This work describes a novel location-aware, self-organizing, fault-tolerant peer-to-peer (P2P) overlay network, referred to as Laptop. Network locality-aware considerations are a very important metric for designing a P2P overlay network. Several network proximity schemes have been proposed to enhance the routing efficiency of existing DHT-based overlay networks. However, these schemes have some drawbacks such as high overlay network and
Chi-jen Wu; De-kai Liu; Ren-hung Hwang
Landsat-7 is scheduled for launch on April 15 from the Western Test Range at Vandenberg Air Force Base, Calif., on a Delta-H expendable launch vehicle. The Landsat 7 satellite consists of a spacecraft bus being provided by Lockheed Martin Missiles and Space (Valley Forge, Pa.) and the Enhanced Thematic Mapper Plus instrument built by Raytheon (formerly Hughes) Santa Barbara Remote Sensing (Santa Barbara, Calif.). The instrument on board Landsat 7 is the Enhanced Thematic Mapper Plus (ETM+). ETM+ improves upon the previous Thematic Mapper (TM) instruments on Landsat's 4 and 5 (Fig. la and lb). It includes the previous 7 spectral bands measuring reflected solar radiation and emitted thermal emissions but, in addition, includes a new 15 in panchromatic (visible-near infrared) band. The spatial resolution of the thermal infrared band has also been improved to 60 m. Both the radiometric precision and accuracy of the sensor are also improved from the previous TM sensors. After being launched into a sun-synchronous polar orbit, the satellite will use on-board propulsion to adjust its orbit to a circular altitude of 438 miles (705 kilometers) crossing the equator at approximately 10 a.m. on its southward track. This orbit will place Landsat 7 along the same ground track as previous Landsat satellites. The orbit will be maintained with periodic adjustments for the life of the mission. A three-axis attitude control subsystem will stabilize the satellite and keep the instrument pointed toward the Earth to within 0.05 degrees. Later this year, plans call for the NASA Earth Observation System (EOS) Terra (AM-1) observatory and the experimental EO-1 mission to closely follow Landsat-7's orbit to support synergistic research and applications from this new suite of terrestrial sensor systems. Landsat is the United States' oldest land-surface observation satellite system, with satellites continuously operating since 1972. Although the program has scored numerous successes in scientific and resource-management applications, Landsat has had a tumultuous history of management and funding changes over its nearly 27-year history. Landsat-7 marks a new direction in the program to reduce the cost of data and increase systematic global coverage for use in global change research as well as commercial and regional applications. With the passage of the Land Remote Sensing Policy Act in 1992, oversight of the Landsat program began to shift from the commercial sector to the federal government. NASA integrated Landsat-7 into its EOS science program in 1994. Landsat-7 is managed and operated jointly by NASA and U.S. Geological Survey (USGS). As a result, the costs of acquiring observations from
Williams, Darrel; Irons, James; Goward, Samuel N.; Masek, Jefery
Summary of Concrete Overlays Existing concrete pavement with surface distresses Prepared surface Monolithic pavement with new concrete surface Existing asphalt pavement with surface distresses Milled pavement with asphalt surface distresses Milled and cleaned surface New 2Â5 in. (5.1Â12.7 cm) bonded
In this paper we proposed a novel overlay alignment method using two sets of identical photonic crystals (PhCs). In this method the reflection or transmission spectrum of the two overlaid photonic crystals is measured to help wafer tilt, yaw rotation, and translation aligning. The initial testing results with two 1D photonic crystals and analysis of the alignment accuracy are presented.
Can Peng; Keith Morton; Zhaoning Yu; Stephen Y. Chou
Research is being conducted to develop criteria for selecting weld overlay coatings for erosion mitigation in circulated fluidized beds. Twelve weld overlay alloys were deposited on 1018 steel substrates using plasma arc welding. Ten samples from each coating were prepared for erosion testing. All selected coatings were erosion tested at 400C and their erosion resistance and microstructure evaluated. Steady state erosion rates were similar for several weld overlay coatings (Ultimet, Inconel-625, Iron-Aluminide, 316L SS, and High Chromium Cast Iron) and were considerably lower than the remaining coating evaluated. These coatings had different base (Co, Fe, Ni-base). No correlations were found between room temperature microhardness of the weld overlay coatings and their erosion resistance at elevated temperature, although this criteria is often thought to be an indicator of erosion resistance. It was suggested that the coatings that showed similar erosion rates may have similar mechanical properties such as fracture strength, toughness and work hardening rates at this temperature. During the past quarter, Iron-Aluminide, Inconel-625, and 316L SS coatings were selected for more detailed investigations based upon the preliminary erosion test results. Microhardness tests were performed on eroded samples to determine the size of the work hardened zone and change in coatings hardness due to erosion. The work hardened zone was correlated with erosion resistance of the coatings. Additional Iron-Aluminide, Inconel-625, and 316L SS coatings were deposited on 1018 steel substrates.
Levin, B. F.; Dupont, J. N.; Marder, A. R.
The synchronization problems involved in mixing computer graphics with a video signal are outlined, and it is shown how two components solve them. The components, a video encoder and a genlocking digitizer facilitate overlays of digital computer graphics and\\/or text data onto a standard analog NTSC (National Television System Committee) or PAL baseband television signal. The mapping of the clock
John A. Eldon
The potential of the Landsat spacecraft in applications related to agriculture is demonstrated by the examples of assessing the damage to the Brazilian coffee crop due to freezing temperatures on July 17-18, 1975; and damage assessment in the state of Iowa, following a tornado which struck a corn and soybean producing region on June 13, 1976. Some techniques which have been used to measure snow covers on the basis of Landsat data are also noted. The advantages that are expected to accrue from the installation of sophisticated equipment on the third and fourth Landsat spacecraft, scheduled to be launched in 1978 and 1981, respectively, are reviewed.
Walter, L. S.
Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska and Hawaii. The Non-U.S. Standard Catalog identifies all the remaining coverage. Sections 1 and 2 describe the contents and format for the catalogs and the associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles. Sections 4 and 5 cover LANDSAT-1 and LANDSAT-2 coverage, respectively.
Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska and Hawaii. The Non-U.S. Standard Catalog identifies all the remaining coverage. Section 1 and 2 describe the contents and format for the catalogs and the associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles. Sections 4 and 5 cover LANDSAT-1 and LANDSAT-2 coverage, respectively.
Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska and Hawaii. The Non-U.S. Standard Catalog identifies all the remaining coverage. Sections 1 and 2 describe the contents and format for the catalogs and the associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles. Sections 4 and 5 cover LANDSAT-1 and LANDSAT-2 coverage, respectively.
As we increase our dependency upon networked communication, the incentive to compromise and degrade network performance increases for those who wish to disrupt the flow of information. Attacks that lead to such compromise and degradation can come in a variety of forms, including distributed denial of service (DDoS) attacks, cutting wires, jamming transmissions, and monitoring/eavesdropping. Users can protect themselves from monitoring by applying cryptographic techniques, and the recent work has explored developing networks that react to DDoS attacks by locating the source(s) of the attack. However, there has been little work that addresses preventing the other kinds of attacks as opposed to reacting to them. Here, we discuss how network overlays can be used to complicate the job of an attacker that wishes to prevent communication. To amplify our point, we focus briefly on a study of preventing DDoS attacks by using overlays.
Keromytis, Angelos D.; Misra, Vishal; Rubenstein, Daniel
The Non-U.S. Standard Catalog lists Non-U.S. imagery acquired by LANDSAT 1 and LANDSAT 2 which has been processed and input to the data files during the referenced month. Data, such as date required, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found are also given.
The U.S. Standard Catalog lists U.S. imagery acquired by LANDSAT 1 and LANDSAT 2 which has been processed and input to the data files during the referenced month. Data, such as date acquired, cloud cover and image quality, are given for each scene. The microfilm roll and frame on which the scene may be found is also given.
According to the ITRS roadmap , the overlay requirement for the 28nm node is 8nm. If we compare this number with the performance given by tool vendors for their most advanced immersion systems (which is < 3nm), there seems to remain a large margin. Does that mean that today's leading edge Fab has an easy life? Unfortunately not, as other contributors affecting overlay are emerging. Mask contributions and so-called non-linear wafer distortions are known effects that can impact overlay quite significantly. Furthermore, it is often forgotten that downstream (post-litho) processes can impact the overlay as well. Thus, it can be required to compensate for the effects of subsequent processes already at the lithography operation. Within our paper, we will briefly touch on the wafer distortion topic and discuss the limitations of lithography compensation techniques such as higher order corrections versus solving the root cause of the distortions. The primary focus will be on the impact of the etch processes on the pattern placement error. We will show how individual layers can get affected differently by showing typical wafer signatures. However, in contrast to the above-mentioned wafer distortion topic, lithographic compensation techniques can be highly effective to reduce the placement error significantly towards acceptable levels (see Figure 1). Finally we will discuss the overall overlay budget for a 28nm contact to gate case by taking the impact of the individual process contributors into account.
Ruhm, Matthias; Schulz, Bernd; Cotte, Eric; Seltmann, Rolf; Hertzsch, Tino
Zusammenfassung Das Internet ist heute eine globale Infrastruktur, deren ständige Verfügbarkeit mehr oder weniger als gegeben angenommen wird.\\u000a Die Einführung neuer Technologien (z.?B. Multicast, IPv6) in diese Infrastruktur erweist sich aus unterschiedlichen Gründen\\u000a als schwierig. Vielmehr haben sich Overlay-Netze in diesem Kontext als Innovationsmotor etabliert. Diese werden von Endgeräten\\u000a am Netzrand aufgespannt, benötigen somit keine neuen Komponenten in der Netzinfrastruktur und
Oliver P. Waldhorst; Roland Bless; Martina Zitterbart
The Nyiragongo volcano in the Congo erupted on January 17, 2002, and subsequently sent streams of lava into the city of Goma on the north shore of Lake Kivu. More than 100 people were killed, more than 12,000 homes were destroyed, and hundreds of thousands were forced to flee the broader community of nearly half a million people. This Landsat satellite image shows the volcano (right of center), the city of Goma, and surrounding terrain. Image data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite were used to supply a partial map of the recent lava flows (red overlay), including a complete mapping of their intrusion into Goma as of January 28, 2002. Lava is also apparent within the volcanic crater and at a few other locations. Thick (but broken) cloud cover during the ASTER image acquisition prevented a complete mapping of the lava distribution, but future image acquisitions should complete the mapping.Goma has a light pink speckled appearance along the shore of Lake Kivu. The city airport parallels, and is just right (east) of, the larger lava flow. Nyiragongo peaks at about 3,470 meters (11,380 feet) elevation and reaches almost exactly 2,000 meters (6,560 feet) above Lake Kivu. The shorter but much broader Nyamuragira volcano appears in the upper left.Goma, Lake Kivu, Nyiragongo, Nyamuragira and other nearby volcanoes sit within the East African Rift Valley, a zone where tectonic processes are cracking, stretching, and lowering the Earth's crust. Volcanic activity is common here, and older but geologically recent lava flows (magenta in this depiction) are particularly apparent on the flanks of the Nyamuragira volcano.The Landsat image used here was acquired on December 11, 2001, about a month before the eruption, and shows an unusually cloud-free view of this tropical terrain. Minor clouds and their shadows were digitally removed to clarify the view and topographic shading derived from the SRTM elevation model was added to the Landsat image. Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and substantially helps in analyzing the large and growing Landsat image archive. This Landsat 7 Thematic Mapper image was provided to the SRTM and ASTER projects by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center, Sioux Falls, S.D.With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) will image Earth for several years to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy,Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. ASTER is providing scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter(approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's
A novel method for performing real-time acquisition and processing Landsat/EROS data covers all aspects including radiometric and geometric corrections of multispectral scanner or return-beam vidicon inputs, image enhancement, statistical analysis, feature extraction, and classification. Radiometric transformations include bias/gain adjustment, noise suppression, calibration, scan angle compensation, and illumination compensation, including topography and atmospheric effects. Correction or compensation for geometric distortion includes sensor-related distortions, such as centering, skew, size, scan nonlinearity, radial symmetry, and tangential symmetry. Also included are object image-related distortions such as aspect angle (altitude), scale distortion (altitude), terrain relief, and earth curvature. Ephemeral corrections are also applied to compensate for satellite forward movement, earth rotation, altitude variations, satellite vibration, and mirror scan velocity. Image enhancement includes high-pass, low-pass, and Laplacian mask filtering and data restoration for intermittent losses. Resource classification is provided by statistical analysis including histograms, correlational analysis, matrix manipulations, and determination of spectral responses. Feature extraction includes spatial frequency analysis, which is used in parallel discriminant functions in each array processor for rapid determination. The technique uses integrated parallel array processors that decimate the tasks concurrently under supervision of a control processor. The operator-machine interface is optimized for programming ease and graphics image windowing.
In July 1972, NASA launched the Earth Resource Technology Satellite (ERTS), the first of what was to be the series of Earth-observing satellites we now know as the Landsat system. This system, originally conceived in the 1960's within the US Department of the Interior and US Geological Survey (USGS), has continued with little interruption for over 40 years, creating the longest record of satellite-based global land observations. The current USGS archive of Landsat images exceeds 4 million scenes, and the recently launched Landsat 8 platform will extend that archive to nearly 50 years of observations. Clearly, these observations are critical to the study of Earth system processes, and the interaction between these processes and human activities. However, the seven successful Landsat missions represent more of an ad hoc program than a long-term record of consistent observations, due largely to changing Federal policies and challenges finding an operational home for the program. Technologically, these systems evolved from the original Multispectral Scanning System (MSS) through the Thematic Mapper and Enhanced Thematic Mapper Plus (ETM+) systems, to the current Observational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) systems. Landsat data were collected globally by a network of international cooperators having diverse data management policies. Much of the oldest data were stored on archaic media that could not be retrieved using modern media readers. Collecting these data from various sensors and sources, and reconstructing them into coherent Earth observation records, posed numerous challenges. We present here a brief overview of work done to overcome these challenges and create a consistent, long-term Landsat observation record. Much of the current archive was 'repatriated' from international cooperators and often required the reconstruction of (sometimes absent) metadata for geo-location and radiometric calibration. The older MSS data, some of which had been successfully retrieved from outdated wide band video media, required similar metadata reconstruction. TM data from Landsats 4 and 5 relied on questionable on-board lamp data for calibration, thus the calibration history for these missions was reconstructed to account for sensor degradation over time. To improve continuity between platforms, Landsat 7 and 8 missions employed 'under-flight' maneuvers to reduce inter-calibration error. Data from the various sensors, platforms and sources were integrated into a common metadata standard, with quality assurance information, to ensure understandability of the data for long-term preservation. Because of these efforts, the current Landsat archive can now support the creation of the long-term climate data records and essential climate variables required to monitor changes on the Earth's surface quantitatively over decades of observations.
Meyer, D. J.; Dwyer, J. L.; Steinwand, D.
Unstructured overlays form an important class of peer-to-peer networks, notably when content-based searching is at stake. The construction of these overlays, which is es- sentially a membership management issue, is crucial. Ideally, the resulting overlays should have low diameter and be resilient to massive node failures, which are both characteristic properties of random graphs. In addition, they should be able
Spyros Voulgaris; Daniela Gavidia; Maarten Van Steen
Structured peer-to-peer overlay networks provide a substrate for the construction of large-scale, decentralized applications, including distributed storage, group communication, and content distribution. These overlays are highly resilient; they can route messages correctly even when a large fraction of the nodes crash or the network partitions. But current overlays are not secure; even a small fraction of malicious nodes can prevent
Miguel Castro; Peter Druschel; Ayalvadi J. Ganesh; Antony I. T. Rowstron; Dan S. Wallach
Isothermal-isobaric Molecular Dynamics (MD) simulation of a submonolayer Pb film in c(2x2) ordered structure adsorbed on a Cu(100) substrate showed retention of order to high T. The Embedded Atom Method (EAM) calculated the energy of atoms of overlayer and substrate. The time-averaged squared modulus of the two dimensional structure factor for the Pb overlayer measured the order of the overlayer. The results are for increasing T only, and require verification by simulated cooling.
Karimi, M.; Tibbits, P.; Ila, D.; Dalins, I.; Vidali, G.
Petroleum equipment companies currently sell 4130 and 4140 steel pipe with alloy 625 (UNS N06625) weld overlay for Oil Patch applications. Alloy 686 (UNS N06686), because of it`s superior corrosion resistance, is currently being evaluated as a replacement material for alloy 625. Mechanical properties and Slow Strain Rate test results for the alloy 686 weld overlay are discussed relative to the alloy 625 weld overlay.
Hibner, E.L. [Inco Alloys International, Inc., Huntington, WV (United States); Maligas, M.N.; Vicic, J.C. [FMC Corp., Houston, TX (United States)
The status of the Brazilian LANDSAT facilities and the results achieved are presented. In addition, a LANDSAT product sales/distribution analysis is provided. Data recording and processing capabilities and planned products are addressed.
Parada, N. D. J. (principal investigator); Barbosa, M. N.
The radiometric requirements, internal calibration, sensor output format, geometric characteristics, and data processing constants for the LANDSAT 4 multispectral scanner and thematic mapper are described. In addition, telemetry format, onboard computer reports, and LANDSAT 4 communications are discussed.
Launched in 1982 and 1984 respectively, the Landsat-4 and -5 Thematic Mappers (TM) are the backbone of an extensive archive of moderate resolution Earth imagery. However, these sensors and their data products were not subjected to the type of intensive monitoring that has been part of the Landsat-7 system since its launch in 1999. With Landsat-4's 11 year and Landsat-5's 20+ year data record, there is a need to understand the historical behavior of the instruments in order to verify the scientific integrity of the archive and processed products. Performance indicators of the Landsat-4 and -5 thermal bands have recently been extracted from a processing system database allowing for a more complete study of thermal band characteristics and calibration than was previously possible. The database records responses to the internal calibration system, instrument temperatures and applied gains and offsets for each band for every scene processed through the National Landsat Archive Production System (NLAPS). Analysis of this database has allowed for greater understanding of the calibration and improvement in the processing system. This paper will cover the trends in the Landsat-4 and -5 thermal bands, the effect of the changes seen in the trends, and how these trends affect the use of the thermal data.
Barsi, J.A.; Chander, G.; Markham, B.L.; Higgs, N.
Sun calibration data from Landsat-2 are presented and compared with those from Landsat-1 (ERTS-1). The data support the hypothesis that organic contamination caused the poor performance of the Landsat-1 sun calibration mirror, since extra cleanliness precautions were taken with the Landsat-2 mirror. These precautions are described; of particular importance was the aluminum foil covering kept close to the reflective surfaces of the second mirror during the prelaunch period.
Horan, J. J.; Schwartz, D. S.; Love, J. D.
Algorithms and procedures necessary to merge aircraft synthetic aperture radar (SAR) and LANDSAT multispectral scanner (MSS) imagery were determined. The design of a SAR/LANDSAT data merging system was developed. Aircraft SAR images were registered to the corresponding LANDSAT MSS scenes and were the subject of experimental investigations. Results indicate that the registration of SAR imagery with LANDSAT MSS imagery is feasible from a technical viewpoint, and useful from an information-content viewpoint.
Maurer, H. E. (editor); Oberholtzer, J. D. (editor); Anuta, P. E. (editor)
The Landsat Thematic Mapper (TM) represents significant improvements in spatial, spectral, and radiometric resolution over the older Multispectral Scanner System (MSS). For the last three years, NASA has conducted the Landsat Image Data Quality Analysis (LIDQA) program to quantify the performance of the TM on the Landsat-4 and 5 spacecraft. As part of this program, analysis of the TM imagery to extract the overall system modulation transfer function (MTF) has been performed. In this paper, the San Mateo Bridge in San Francisco is described as a target for calculation of the line spread function and MTF. The analysis of two TM scenes, one from 12/31/82 and one from 8/12/83, yielded effective-instantaneous-field-of-views (EIFOVs) of 40.8 meters and 48.6 meters, respectively. These values are compared with the 33.8 meter EIFOV predicted by component modelling of the TM sensor, and the differences discussed.
Schowengerdt, R.; Archwamety, C.; Wrigley, R. C.
The Landsat Image Data Quality Analysis (LIDQA) Program conducted by NASA has the objective to quantify the performance of the Thematic Mapper (TM) on the Landsat-4 and Landsat-5 spacecraft. The interest in the spatial resolution performance of the TM is partly related to the decrease of the instantaneous field of view (IFOV) from 80 m for the MSS to 30 m for the TM. Studies related to the preflight line spread function (LSF), square wave response (SWR), and theoretical component modeling of the TM system modulation transfer function (MTF) have been conducted. However, the need remains to estimate the MTF of the complete system. The present paper is concerned with investigations related to this task. Attention is given to three approaches for measuring the MTF of the TM system from imagery.
Schowengerdt, R. A.; Archwamety, C.; Wrigley, R. C.
“Now is the time to pull strings…use your connections,” Congressman Dave McCurdy (D- OK-4) told a Geosat meeting June 23 in Washington, D.C. McCurdy was talking to the board of the satellite users corporation about the current congressional negotiations for the Landsat 6 development budget.President Reagan requested $34.1 million for Landsat 6 for FY89. The House and Senate appropriations committees have budgeted $20.3 million, and the Department of Defense is expected to make up the shortfall. No provisions have been made for the $34 million scheduled for Landsat hardware. Final appropriations will not be decided until the House-Senate committee conference session on the 1989 budget.
Wainger, Lisa A.
The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) project is creating a record of forest disturbance and regrowth for North America from the Landsat satellite record, in support of the carbon modeling activities. LEDAPS relies on the decadal Landsat GeoCover data set supplemented by dense image time series for selected locations. Imagery is first atmospherically corrected to surface reflectance, and then change detection algorithms are used to extract disturbance area, type, and frequency. Reuse of the MODIS Land processing system (MODAPS) architecture allows rapid throughput of over 2200 MSS, TM, and ETM+ scenes. Initial ("Beta") surface reflectance products are currently available for testing, and initial continental disturbance products will be available by the middle of 2006.
Masek, Jeffrey G.
The author has identified the following significant results. Large area LANDSAT yield estimates were generated. These results were compared with estimates computed using a meteorological yield model (CCEA). Both of these estimates were compared with Kansas Crop and Livestock Reporting Service (KCLRS) estimates of yield, in an attempt to assess the relative and absolute accuracy of the LANDSAT and CCEA estimates. Results were inconclusive. A large area direct wheat prediction procedure was implemented. Initial results have produced a wheat production estimate comparable with the KCLRS estimate.
Nalepka, R. F.; Colwell, J. E. (principal investigators); Rice, D. P.; Bresnahan, P. A.
The parameters of diffusion patterns of atmospheric pollutants under different conditions were investigated for use in the Gaussian model for calculation of pollution concentration. Value for the divergence pattern of concentration distribution along the Y axis were determined using LANDSAT images. Multispectral scanner images of a point source plume having known characteristics, wind and temperature data, and cloud cover and solar elevation data provided by LANDSAT, were analyzed using the 1-100 system for image analysis. These measured values are compared with pollution transport as predicted by the Pasquill-Gifford, Juelich, and Hoegstroem atmospheric models.
Torsani, J. A.; Viswanadham, Y.
, h& ? 60 mils, s = 60 mils, and w = 160 mils. 26. Theoretical values of effective permittivity for c?& = 10. 5, e?z = 10. 5, hz = 25 mils, s = 10 mils, and w = 30 mils. 27. Field ratio for even- and odd-mode coupled microstrip lines. 28. Coupled... frequency. 32. Effective permittivity as a function of dielectric overlay thickness for e?r = c?z = 2 33, h = s = 60 mils, w = 160 mils. 33. Experimental values of isolation for compensated and uncompensated coupler. 34. Characteristic impedance...
Klein, James Louis
LANDSAT 1 and 2 operations were described, giving detailed charts and tables of their performances since 1972. Orbital parameters, attitude control subsystem, telemetry subsystem, orbit adjust subsystem, and magnetic moment compensating assembly were some of the main parameters discussed.
An error model for quantifying the magnitudes and variability of errors generated in the areas of polygons during spatial overlay of vector geographic information system layers is presented. Numerical simulation of polygon boundary displacements was used to propagate coordinate errors to spatial overlays. The model departs from most previous error models in that it incorporates spatial dependence of coordinate errors at the scale of the boundary segment. It can be readily adapted to match the scale of error-boundary interactions responsible for error generation on a given overlay. The area of error generated by overlay depends on the sinuosity of polygon boundaries, as well as the magnitude of the coordinate errors on the input layers. Asymmetry in boundary shape has relatively little effect on error generation. Overlay errors are affected by real differences in boundary positions on the input layers, as well as errors in the boundary positions. Real differences between input layers tend to compensate for much of the error generated by coordinate errors. Thus, the area of change measured on an overlay layer produced by the XOR overlay operation will be more accurate if the area of real change depicted on the overlay is large. The model presented here considers these interactions, making it especially useful for estimating errors studies of landscape change over time. ?? 2005 The Ohio State University.
Gaeuman, D.; Symanzik, J.; Schmidt, J.C.
Results are presented on the all-optical tuning of the attenuation bands of an optical fiber long period grating utilizing a photochromic outcladding overlayer. The outcladding overlayer consists of PMMA polymer doped with the photochromic molecule of spiropyran. The spectral transmission characteristics of the long period grating are reversibly altered using sequential exposures of 355 nm and 532 nm, Nd:YAG laser
Maria Konstantaki; Stavros Pissadakis
A key technical challenge for overlay multicast is that the highly dynamic multicast members can make data delivery unreliable. In this paper, we address this issue in the context of live media streaming by exploring 1) how to construct a stable multicast tree that minimizes the negative impact of frequent member departures on an existing overlay and 2) how to
Guang Tan; Stephen A. Jarvis
performance on high-speed Ethernet networks [6,17]. Providing the same Ethernet abstraction on high-end dataVirtual TCP Offload: Optimizing Ethernet Overlay Performance on Advanced Interconnects Zheng Cui@northwestern.edu ABSTRACT Ethernet overlay networks are a powerful tool for virtu- alizing networked applications
Dinda, Peter A.
Verme: Worm Containment in Overlay Networks Filipe Freitas1 , Edgar Marques1 , Rodrigo Rodrigues2 Max Planck Institute for Software Systems (MPI-SWS) Abstract Topological worms, such as those random scanning worms be- cause they have knowledge of a subset of the overlay nodes, and choose
Overlay networks are widely used to deploy func- tionality at edge nodes without changing network routers. Each node in an overlay network maintains connections with a number of peers, forming a graph upon which a distributed application or service is implemented. In an \\
Atul Singh; Tsuen-wan Ngan; Peter Druschel; Dan S. Wallach
Defending against Eclipse attacks on overlay networks Atul SinghÂ½Â£ Miguel CastroÂ¾ Peter Druschel, it can "eclipse" correct nodes and pre- vent correct overlay operation. This Eclipse attack is more general than the Sybil attack. Attackers can use a Sybil attack to launch an Eclipse attack by inventing
Defending against Eclipse attacks on overlay networks Atul Singh1 Miguel Castro2 Peter Druschel1, it can "eclipse" correct nodes and pre- vent correct overlay operation. This Eclipse attack is more general than the Sybil attack. Attackers can use a Sybil attack to launch an Eclipse attack by inventing
it impossible for a "small" coalition of malicious peers to correlate overlay addresses to hosts for censorship, censorship-resistant 1. Introduction and motivation Overlay networks have been receiving a lot of atten- tion to the physical Internet address of the destination host. It must be made difficult for an adversary to build
We propose an application level multicast approach, Topology Aware Grouping (TAG), which exploits underlying network topology information to build efficient overlay networks among multicast group members. TAG uses information about path overlap among members to construct a tree that reduces the overlay relative delay penalty, and reduces the number of duplicate copies of a packet on the same link. We
Minseok Kwon; Sonia Fahmy
Exactly computing map overlays using rational numbers W. Randolph Franklin ECSE Dept, 6026 JEC://wrfranklin.org/ Keywords: overlay, roundoff error, rational numbers, topology, intersection We present a solution as rational numbers, or vulgar fractions composed of a numerator divided by a denominator. Because the result
Franklin, W. Randolph
Conventional fossil fired boilers have been retrofitted with low NO(sub)x burners in order for the power plants to comply with new clean air regulations. Due to the operating characteristics of these burners, boiler tube sulfidation corrosion typically has been enhanced resulting in premature tube failure. To protect the existing panels from accelerated attack, weld overlay coatings are typically being applied. By depositing an alloy that offers better corrosion resistance than the underlying tube material, the wastage rates can be reduced. While Ni-based and stainless steel compositions are presently providing protection, they are expensive and susceptible to failure via corrosion-fatigue due to microsegregation upon solidification. Another material system presently under consideration for use as a coating in the oxidation/sulfidation environments is iron-aluminum. These alloys are relatively inexpensive, exhibit little microsegregation, and show excellent corrosion resistance. However, their use is limited due to weldability issues and their lack of corrosion characterization in simulated low NO(sub)x gas compositions. Therefore a program was initiated in 1996 to evaluate the use of iron-aluminum weld overlay coatings for erosion/corrosion protection of boiler tubes in fossil fired boilers with low NO(sub)x burners. Investigated properties included weldability, corrosion behavior, erosion resistance, and erosion-corrosion performance.
Banovic, S.W.; DuPont, J.B.; Levin, B.F.; Marder, A.R.
We have previously reported on an overlay metrology simulation platform, used for modeling both the effects of overlay metrology tool behavior and the impact of target design on the ultimate metrology performance. Since our last report, the simulation platform has been further enhanced, consisting now of eleven PCs and running commercial software both for lithography (PROLITH) and rigorous Maxwell calculations (EM-Suite). In this paper we report on the validation of the metrology simulations by comparing them to both analytical calculations and to experimental results. The analytical validation is based on the classical calculation of the diffraction of a polarized plane wave from a perfectly conducting half plane. For the experimental validation, we chose an etched silicon wafer manufactured by International SEMATECH (ISMT) and characterized at National Institute of Science and Technology (NIST). The advantages of this wafer are its well known topography and its suite of different metrology targets. A good fit to both analytical and experimental results is demonstrated, attesting to the capabilities of our enhanced simulation platform. The results for both the analytical and experimental validations are presented.
Seligson, Joel L.; Golovanevsky, Boris; Poplawski, Jorge M.; Adel, Michael E.; Silver, Richard M.
Micro scale laser bulge forming (?LBF) shows great potential in fabricating high precision and high-aspect-ratio metallic micro components. The present paper investigated the effect of the confining overlay in ?LBF experimentally. The surface morphology of micro bulged parts of pure copper foils with and without confining overlay was explored through the scanning electron microscope. The surface features of quartz glasses with different thickness shocked by single and multiple laser pulses were observed using the optical microscope. The effect of thickness of the confining overlay on the maximum bulging height of micro parts was investigated. Experiments reveal that the application of the confining overlay in ?LBF has significant influence on both the surface morphology and plastic deformation of micro bulged parts. The change of laser ablation mode is responsible for forming results. In addition, there is a moderate thickness of the confining overlay to induce noticeable plastic deformation without failure.
Zheng, Chao; Sun, Sheng; Zhang, Guofang; Song, Libin; Ji, Zhong
Michelle A. Bouchard, John L. Dwyer and Brian Granneman. American Geophysical Union, Fall Meeting 2009, abstract #GC51A-0708 Landsat data from the Global Land Survey (GLS) dataset for year 2000 was mosaicked to form a Yukon River Basin image map that is referenced to a geodetic base. It was produc...
Presented is a compendium of the outstanding Landsat scenes of the Earth's surface. It is directed to college and high school teachers, resource specialists, researchers, outdoorsmen, travelers, the general public, and serious students of geology or geography. The images are presented in color and at a scale and resolution that specify many…
Short, Nicholas M.; And Others
The Boreal Ecosystem-Atmospheric Study (BOREAS) Staff Science Satellite Data Acquisition Program focused on providing the research teams with the remotely sensed satellite data products they needed to compare and spatially extend point results. The Earth Resources Technology Satellite (ERTS) Program launched the first of a series of satellites (ERTS-1) in 1972. Part of the NASA Earth Resources Survey Program, the ERTS Program and the ERTS satellites were later renamed Landsat to better represent the civil satellite program's prime emphasis on remote sensing of land resources. Landsat satellites 1 through 5 carry the Multispectral Scanner (MSS) sensor. Canada for Remote Sensing (CCRS) and BOREAS personnel gathered a set of MSS images of the BOREAS region from Landsat satellites 1, 2, 4, and 5 covering the dates of 21 Aug 1972 to 05 Sep 1988. The data are provided in binary image format files of various formats. The Landsat MSS imagery is available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).
Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Strub, Richard; Newcomer, Jeffrey A.
Analysis of sixty-four scan lines representing diverse conditions across satellites, channels, scanners, locations and cloud cover confirms that Landsat data are autocorrelated and consistently follow an Arima (1,0,1) pattern. The AR parameter varies significantly with location and the MA coefficient with cloud cover. Maximum likelihood classification functions are considerably in error unless this autocorrelation is compensated for in sampling.
Craig, R. G.; Labovitz, M. L.
The FOLD data base lists all Landsat CCT's held by participating agencies. Duplicate CCT listings are maintained when more than one agency holds identical CCT's; this permits the user to select the most convenient site to obtain a copy. Copies of the listing are distributed by EDC to contributing agencies and other selected offices.
U.S. Geological Survey
The FOLD data base lists all Landsat scenes held by participating agencies. Duplicate scene listings are maintained when more than one agency holds identical scenes; this permits the user to select the most convenient site to obtain a copy. Copies of the listing are distributed by EDC to contributing agencies and other selected offices.
U.S. Geological Survey
The FOLD data base lists all Landsat CCT's held by participating agencies. Duplicate CCT listings are maintained when more than one agency holds identical CCT's; this permits the user to select the most convenient site to obtain a copy. Copies of the listing are distributed by EDC to contributing agencies and other selected offices.
U.S. Geological Survey
An automatic cloud cover assessment algorithm was developed for the Landsat 7 ground system. A scene dependent approach that employs two passes through ETM+ data was developed. In pass one, the reflective and thermal properties of scene features are used to establish the presence or absence of clouds in a scene. If present, a scene-specific thermal profile for clouds is
Richard R. Irish
The use of multispectral imagery obtained from LANDSAT for mapping purposes is discussed with emphasis on geometric rectification, image resolution, and systematic topographic mapping. A method is given for constructing 1:250,000 scale maps. The limitations for satellite cartography are examined.
Dejesusparada, N. (principal investigator); Alburquerque, P. C. G.
Viewgraphs and photographs depict the scope and purpose of the LANDSAT 4 mission as well as all satellite systems. The components and major functions of the flight and ground segments, operational support, communication links, and the hardware and interfaces for processing MSS and TM images are covered.
A variety of man-made objects have been sent into outer space for decades, and as a very large and distinguished group, they have sent back important data. NASA has been at the forefront of these efforts here in the United States, and the Landsat Program has certainly been quite successful since its inception in the early 1970s. This website provides a wealth of information on the Landsat Program, and visitors can learn about its work in remote sensing. Visitors can use the right-hand side of the page to learn about different Landsat missions ranging from the original Landsat all the way up to Landsat Seven, which was launched in 1999. Each section contains information on Landsat's orbit, its instruments, and its vital statistics. Finally, a "Did You Know" section provides some key facts about some of the accomplishments of the Landsat program.
Coatings are frequently applied to gas turbine blades and vanes to provide protection against oxidation and corrosion. The results of an experimental and analytical study to develop a constitutive model for an overlay coating is presented. Specimens were machined from a hot isostatically pressed billet of PWA 286. The tests consisted of isothermal stress relaxation cycles with monotonically increasing maximum strain and were conducted at various temperatures. The results were used to calculate the constants for various constitutive models, including the classical, the Walker isotropic, a simplified Walker, and Stowell models. A computerized regression analysis was used to calculate model constants from the data. The best fit was obtained for the Walker model, with the simplified Walker and classical models close behind.
Nissley, D. M.; Swanson, G. A.
Landsat 1 launched in February 1972. This began a more than 37-year mission to provide the world with mid-resolution satellite data coverage. Although data were always publically available, the cost of the data has always been prohibitive for either broad regional to global studies, or research requiring long-term studies with high temporal frequency. In order to overcome the cost-barrier, the entire Landsat archive, over 2.3 million scenes, was offered for free at the end of December 2008. Over 1,000,000 scenes were downloaded in the first ten months, surpassing all data distribution in the history of the Landsat mission combined. Technical improvements for radiometric and geometric consistency are still underway, over a year later. In addition, capabilities for bulk metadata access and bulk downloading were just implemented in the fall of 2009. Data does not permanently reside in a processed format. Data is processed as requested, or, in some cases, as soon as it is acquired, and then rolled off as improved processing parameters are developed or space on the servers is required. This means that data that is downloaded one day, may not be available the next day. But, this approach precludes major reprocessing efforts while maintaining a quick turnaround time for data orders. Depending on demand, maximum processing time is around 27 hours, averages 5 hours, with a minimum of around 10 minutes. Research applications that require bulk metadata access are now able to download as much of the archive metadata as they need. Path/row or latitude/longitude searches are available for the entire Landsat archive. Entire metadata records are not included, only those regarded as important to traditional scene selection, such as cloud cover and quality scores. There is only one Landsat data product, a geo-rectified, terrain-corrected product. For sophisticated users who may want an alternative ‘recipe’ for their data, an alternate projection or resampling algorithm, access to Level 0 data has just become available. Independently created software will be required to read and process these data. In all, the Landsat Project has every interest to enable research that requires a broadening of geographic and temporal coverage at the mid-resolution scale. We hope to prevent the need for individual long-term archive building by providing any scene at any time with the most up-to-date processing parameters.
A simulation of imagery from the Landsat-D thematic mapper was conducted in order to determine its usefulness for urban land-use classification. Aircraft 24-channel multispectral scanner imagery of the Los Angeles area at 7.5-m resolution was processed digitally by means of matrix averaging and image smoothing techniques to simulate the 30-m resolution of the thematic mapper. Mean and standard deviation statistics of training sites for resolutions of 7.5, 15, 30 and 60 m were used to generate final classification maps. Plots of relative standard deviation showed that for larger training sites, as the resolution decreased, the distribution range of density values also decreased, while plots of relative classification accuracies showed that as resolution decreased, classification accuracies for three levels of standard deviation increased. A point of diminishing returns was indicated, however, confirming the utility of the resolution intended for Landsat-D.
Routine acquisition of Landsat 5 Thematic Mapper (TM) data was discontinued recently and Landsat 7 Enhanced Thematic Mapper Plus (ETM+) has an ongoing problem with the scan line corrector (SLC), thereby creating spatial gaps when covering images obtained during the process. Since temporal and spatial discontinuities of Landsat data are now imminent, it is therefore important to investigate other potential satellite data that can be used to replace Landsat data. We thus cross-compared two near-simultaneous images obtained from Landsat 5 TM and the Indian Remote Sensing (IRS)-P6 Advanced Wide Field Sensor (AWiFS), both captured on 29 May 2007 over Los Angeles, CA. TM and AWiFS reflectances were compared for the green, red, near-infrared (NIR), and shortwave infrared (SWIR) bands, as well as the normalized difference vegetation index (NDVI) based on manually selected polygons in homogeneous areas. All R2 values of linear regressions were found to be higher than 0.99. The temporally invariant cluster (TIC) method was used to calculate the NDVI correlation between the TM and AWiFS images. The NDVI regression line derived from selected polygons passed through several invariant cluster centres of the TIC density maps and demonstrated that both the scene-dependent polygon regression method and TIC method can generate accurate radiometric normalization. A scene-independent normalization method was also used to normalize the AWiFS data. Image agreement assessment demonstrated that the scene-dependent normalization using homogeneous polygons provided slightly higher accuracy values than those obtained by the scene-independent method. Finally, the non-normalized and relatively normalized ‘Landsat-like’ AWiFS 2007 images were integrated into 1984 to 2010 Landsat time-series stacks (LTSS) for disturbance detection using the Vegetation Change Tracker (VCT) model. Both scene-dependent and scene-independent normalized AWiFS data sets could generate disturbance maps similar to what were generated using the LTSS data set, and their kappa coefficients were higher than 0.97. These results indicate that AWiFS can be used instead of Landsat data to detect multitemporal disturbance in the event of Landsat data discontinuity.
Chen, Xuexia; Vogelmann, James E.; Chander, Gyanesh; Ji, Lei; Tolk, Brian; Huang, Chengquan; Rollins, Matthew
Metrology Marks: Theory and Experiment Mike Adel, Mark Ghinovker, Boris Golovanevsky, Pavel Izikson, Elyakim--In this paper, we provide a detailed analysis of overlay metrology mark and find the mapping between various, Fisher information matrix, grating marks, overlay mark, overlay mark fidelity, overlay metrology. I
Bruckstein, Alfred M.
For close to thirty years, a series of Landsat satellites have imaged the Earth's surface, returning images for use in a number of business, education, government, and science applications. Of course, many of these images have a great deal of aesthetic value, as those who look at them find themselves marveling at vast deltas, fjords, and land use patterns around the globe. This fine exhibit from the Library of Congress includes images transmitted from Landsat 7. These images are are also part of an exhibit in the Library's Geography & Map Reading Room that will be on display until December 31, 2003. Visitors to the online exhibit can look at high-resolution images of remote Akpatok Island in northern Quebec, Dasht-e Kevir (which translates as Great Salt Desert) in Iran, the West Fjords in northwestern Iceland, and about thirty-five other images in total.
The author has identified the following significant results. Temporal registration of synthetic aperture radar data with LANDSAT-MSS data is both feasible (from a technical standpoint) and useful (from an information-content viewpoint). The greatest difficulty in registering aircraft SAR data to corrected LANDSAT-MSS data is control-point location. The differences in SAR and MSS data impact the selection of features that will serve as a good control points. The SAR and MSS data are unsuitable for automatic computer correlation of digital control-point data. The gray-level data can not be compared by the computer because of the different response characteristics of the MSS and SAR images.
Murphrey, S. W. (principal investigator)
The primary payload for the Landsat Data Continuity Mission (LDCM) is the Operational Land Imager (OLI), being built by Ball Aerospace and Technologies, under contract to NASA. The OLI has spectral bands similar to the Landsat-7 ETM+, minus the thermal band and with two new bands, a 443 nm band and 1375 nm cirrus detection band. On-board calibration systems include two solar diffusers (routine and pristine), a shutter and three sets of internal lamps (routine, backup and pristine). Being a pushbroom opposed to a whiskbroom design of ETM+, the system poses new challenges for characterization and calibration, chief among them being the large focal plane with 75000+ detectors. A comprehensive characterization and calibration plan is in place for the instrument and the data throughout the mission including Ball, NASA and the United States Geological Survey, which will take over operations of LDCM after on-orbit commissioning. Driving radiometric calibration requirements for OLI data include radiance calibration to 5% uncertainty (1 q); reflectance calibration to 3% uncertainty (1 q) and relative (detector-to-detector) calibration to 0.5% (J (r). Driving geometric calibration requirements for OLI include bandto- band registration of 4.5 meters (90% confidence), absolute geodetic accuracy of 65 meters (90% CE) and relative geodetic accuracy of 25 meters (90% CE). Key spectral, spatial and radiometric characterization of the OLI will occur in thermal vacuum at Ball Aerospace. During commissioning the OLI will be characterized and calibrated using celestial (sun, moon, stars) sources and terrestrial sources. The USGS EROS ground processing system will incorporate an image assessment system similar to Landsat-7 for characterization and calibration. This system will have the added benefit that characterization data will be extracted as part of the normal image data processing, so that the characterization data available will be significantly larger than for Landsat-7 ETM+.
Markham, Brian L.; Dabney, Philip W.; Storey, James C.; Morfitt, Ron; Knight, Ed; Kvaran, Geir; Lee, Kenton
Interband line pixel misregistrations were determined for the four MSS bands of the Mistassini, Ontario scene and multitemporal registration of LANDSAT-4 products were tested for two different geocoded scenes. Line and pixel misregistrations are tabulated as determined by the manual ground control points and the digital band to band correlation techniques. A method was developed for determining the spectral information content of TM images for forestry applications.
Strome, W. M.; Cihlar, J.; Goodenough, D. G.; Guertin, F. E. (principal investigator); Murphy, J. M.; Grieve, G.; Simard, R.; Horler, D.; Ahern, F. J.
The author has identified the following significant results. The capability of mapping ponds over a very large area was demonstrated, with multidate, multiframe LANDSAT imagery. A small double sample of aircraft data made it possible to adjust a LANDSAT large area census. Terrain classification was improved by using multitemporal LANDSAT data. Waterfowl production was estimated, using remotely determined pond data, in conjunction with FWS estimates of breeding population. Relative waterfowl habitat quality was characterized on a section by section basis.
Colwell, J. E.; Gilmer, D. S. (principal investigators); Work, E. A., Jr.; Rebel, D. L.; Roller, N. E. G.
6. FIRST FLOOR, ROOM 1, BASEBOARD AND PLASTER OVERLAYING SANDSTONE WALLS, LOOKING NORTHWEST - Taylor Run-Yorty Run Schoolhouse, Legislative Routes 62175 (PA Highway 481) & 62161, Monongahela, Washington County, PA
Typical advanced lithographic processes require an overlay tolerance that is approximately 30% of the minimum feature size. To achieve this metrology must be limited to an error budget of 3-5% of the minimum feature size. A discussion of the general use of overlay data for assessment of stepper performance is followed by an overview of key overlay metrology equipment performance parameters (Tool Induced Shift-TIS) and the interaction with the process (Wafer Induced Shift-WIS). The interactions between the target, the process and the equipment will also be reviewed. Finally, use of this information in a case study of overlay target design for Tungsten Chemical Mechanical Planarization (W CMP) will be presented. Relevant process data will demonstrate how such targets can be used to effectively monitor both stepper (systematic error) and metrology tool (random error) performance.
Sullivan, Neal; Shin, Jennifer [Advanced Process Tool Development Group, Digital Semiconductor, Hudson, Massachusetts 01749 (United States)
The Landsat Data Continuity Mission will continue and improve upon the 40-year-old Landsat program. This video examines two uses of Landsat data to monitor agriculture. Both wineries and timber com...
Requirements for thermal data were initially left out of Landsat Data Continuity Mission (LDCM) specifications. This omission represented a departure from data continuity. The earth observing sensors aboard Landsat 4, Landsat 5, and Landsat 7 all collected image data for a single thermal band (1040 1250 nm) with spatial resolutions of 120 m (Landsat 4 and Landsat 5) or 60 m (Landsat 7). NASA is now considering restoration of LDCM requirements for thermal data due to an increasing appreciation for the societal benefits of thermal data. In particular, the emergence of energy balance models for operational water management has raised awareness. Landsat thermal data used in conjunction with energy balance models is proving to be an efficient, cost-effective, and synoptic approach to water management in the western U.S. and world wide. Specifications for LDCM thermal images have been drafted. Two bands are specified to facilitate atmospheric correction for the retrieval of absolute surface temperature. A spatial resolution of 120 m is specified for thermal images after consideration of potential cost impacts and the maturity of thermal detector technology. Currently, NASA is considering including these thermal imaging specifications as an option in a request for proposals (RFP) for a free flying LDCM satellite. An option in the LDCM RFP offers a possibility of continuing the collection of Landsat thermal images and an option falls short of a firm requirement. The presentation will provide the status of thermal imaging requirements for the LDCM.
Irons, J. R.; Markham, B. L.
Shape overlays provide a means of statically imposing a physical region containing specified material properties onto a zoned mesh. In the most general case, material interface boundaries are unrelated to mesh zone boundaries, causing zones to contain a mixture of materials, and the mesh itself is not uniform in physical space. We develop and apply an algorithm for shape overlays on nonorthogonal, nonuniform meshes in two dimensions. Examples of shape generation in a multiblock uid dynamics code are shown.
Tolerable Strains for HMA Overlays over Concrete Pavements By Ashwani Gautam Submitted to the graduate degree program in Civil Engineering and the Graduate Faculty of the University of Kansas School of Engineering in partial fulfillment.../23/09 ii The Thesis Committee for Ashwani Gautam certifies That this is the approved version of the following thesis: Tolerable Strains for HMA Overlays over Concrete Pavements Committee: _______________________ Dr. Jie Han, Chairperson...
REHABILITATION OF CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS USING OVERLAYS A Thesis by SOUMYA SRIRAMAN Submitted to the Graduate College of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... August 1993 Major Subject: Civil Engineering REHABILITATION OF CONTINUOUSLY REINFORCED CONCRETE PAVEMENTS USING OVERLAYS A Thesis by SOUMYA SRIRAMAN Submitted to Texas A&M University in partial fulfillment of the requirements for the degree...
The integration of overlay displays into rifle scopes can transform precision Direct View Optical (DVO) sights into intelligent interactive fire-control systems. Overlay displays can provide ballistic solutions within the sight for dramatically improved targeting, can fuse sensor video to extend targeting into nighttime or dirty battlefield conditions, and can overlay complex situational awareness information over the real-world scene. High brightness overlay solutions for dismounted soldier applications have previously been hindered by excessive power consumption, weight and bulk making them unsuitable for man-portable, battery powered applications. This paper describes the advancements and capabilities of a high brightness, ultra-low power text and graphics overlay display module developed specifically for integration into DVO weapon sight applications. Central to the overlay display module was the development of a new general purpose low power graphics controller and dual-path display driver electronics. The graphics controller interface is a simple 2-wire RS-232 serial interface compatible with existing weapon systems such as the IBEAM ballistic computer and the RULR and STORM laser rangefinders (LRF). The module features include multiple graphics layers, user configurable fonts and icons, and parameterized vector rendering, making it suitable for general purpose DVO overlay applications. The module is configured for graphics-only operation for daytime use and overlays graphics with video for nighttime applications. The miniature footprint and ultra-low power consumption of the module enables a new generation of intelligent DVO systems and has been implemented for resolutions from VGA to SXGA, in monochrome and color, and in graphics applications with and without sensor video.
Hogan, Tim; Edwards, Tim
Currently, overlay measurements are characterized by "recipe", which defines both physical parameters such as focus, illumination et cetera, and also the software parameters such as algorithm to be used and regions of interest. Setting up these recipes requires both engineering time and wafer availability on an overlay tool, so reducing these requirements will result in higher tool productivity. One of the significant challenges to automating this process is that the parameters are highly and complexly correlated. At the same time, a high level of traceability and transparency is required in the recipe creation process, so a technique that maintains its decisions in terms of well defined physical parameters is desirable. Running time should be short, given the system (automatic recipe creation) is being implemented to reduce overheads. Finally, a failure of the system to determine acceptable parameters should be obvious, so a certainty metric is also desirable. The complex, nonlinear interactions make solution by an expert system difficult at best, especially in the verification of the resulting decision network. The transparency requirements tend to preclude classical neural networks and similar techniques. Genetic algorithms and other "global minimization" techniques require too much computational power (given system footprint and cost requirements). A Bayesian network, however, provides a solution to these requirements. Such a network, with appropriate priors, can be used during recipe creation / optimization not just to select a good set of parameters, but also to guide the direction of search, by evaluating the network state while only incomplete information is available. As a Bayesian network maintains an estimate of the probability distribution of nodal values, a maximum-entropy approach can be utilized to obtain a working recipe in a minimum or near-minimum number of steps. In this paper we discuss the potential use of a Bayesian network in such a capacity, reducing the amount of engineering intervention. We discuss the benefits of this approach, especially improved repeatability and traceability of the learning process, and quantification of uncertainty in decisions made. We also consider the problems associated with this approach, especially in detailed construction of network topology, validation of the Bayesian network and the recipes it generates, and issues arising from the integration of a Bayesian network with a complex multithreaded application; these primarily relate to maintaining Bayesian network and system architecture integrity.
Binns, Lewis A.; Reynolds, Greg; Rigden, Timothy C.; Watkins, Stephen; Soroka, Andrew
Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska, and Hawaii. The Non-U.S. Standard Catalog identifies all the remaining coverage. Sections 1 and 2 describe the contents and format for the catalogs and the associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles.
Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska, and Hawaii. The Non-U.S. Standard Catalog identifies all the remaining coverage. Sections 1 and 2 describe the contents and format for the catalogs and associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles.
Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska and Hawaii. The Non-U.S. Standard Catalog identifies all the remaining coverage. Sections 1 and 2 describe the contents and format for the catalogs and the associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles.
Residual stresses and strains in a tube with circumferential weld overlay were analyzed by the finite element (FE) method. The objective of this work was to develop and verify a FE model, to determine the magnitude and distribution of residual stresses in the weld overlay tube, and to evaluate the significance of two contributing factors to residual stress: (1) difference in material properties between tube and weld material, and (2) thermal gradients in the weld. An axisymmetric FE model was developed to simulate the circumferential two-layer welding process of alloy 625 overlay on SA210 tube. The first layer was modeled as a gas metal arc welding process with filler metal, whereas the autogenous gas tungsten arc welding process was modeled for the second layer. Neutron diffraction technique was used to experimentally determine residual elastic strains in the weld overlay tube. Comparison with the FE results shows overall good agreement. Both the experimental and FE results show high compressive stresses at the inside tube surface and high tensile stresses in the weld overlay. This suggests that weld overlay may be used to relieve tensile or produce compressive stresses at the inside tube surface, which is significant for applications where crack initiation is found at the root pass of the joining weld.
Taljat, B.; Zacharia, T.; Wang, X.L.; Keiser, J.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Feng, Z. [Edison Welding Inst., Columbus, OH (United States); Jirinec, M.J. [Welding Services, Inc., Norcross, GA (United States)
The Department of the Interior (DOI) has the responsibility to preserve and to distribute most Landsat Thematic Mapper (TM) and Multispectral Scanner (MSS) data that have been acquired by the five Landsat satellites operational since July 1972. Data that are still covered by exclusive marketing rights, which were granted by the U.S. Government to the commercial Landsat operator, cannot be distributed by the DOI. As the designated national archive for Landsat data, the U.S. Geological Survey's EROS Data Center (EDC) has initiated two new programs to protect and make available any of the 625,000 MSS scenes currently archived and the 200,000 TM scenes to be archived at EDC by 1995. A specially configured system has begun converting Landsat MSS data from obsolete high density tapes (HDT's) to more dense digital cassette tapes. After transcription, continuous satellite swaths are (1) divided into standard scenes defined by a world reference system, (2) geographically located by latitude and longitude, and (3) assessed for overall quality. Digital browse images are created by subsampling the full-resolution swaths. Conversion of the TM HDT's will begin in the fourth quarter of 1992 and will be conducted concurrently with MSS conversion. Although the TM archive is three times larger than the entire MSS archive, conversion of data from both sensor systems and consolidation of the entire Landsat archive at EDC will be completed by the end of 1994. Some MSS HDT's have deteriorated, primarily as a result of hydrolysis of the pigment binder. Based on a small sample of the 11 terabytes of post-1978 MSS data and the 41 terabytes of TM data to be converted, it appears that to date, less than 2 percent of the data have been lost. The data loss occurs within small portions of some scenes; few scenes are lost entirely. Approximately 10,000 pre-1979 MSS HDT's have deteriorated to such an extent, as a result of hydrolysis, that the data cannot be recovered without special treatment of the tapes. An independent consulting division of a major tape manufacturer has analyzed affected tapes and is confident that restorative procedures can be applied to the HDT's to permit one pass to reproduce the data on another recording media. A system to distribute minimally processed Landsat data will be procured in 1992 and will be operational by mid-1994. Any TM or MSS data in the national archive that are not restricted by exclusive marketing rights will be reproduced directly from the archive media onto user specified computer-compatible media. TM data will be produced either at a raw level (radiometrically and geometrically uncorrected) or at an intermediate level (radiometrically corrected and geometrically indexed). MSS data will be produced to an intermediate level or to a fully corrected level (radiometrically corrected and geometrically transformed to an Oblique Mercator projection). The system will be capable of providing ordered scenes within 48 hours of receipt of order.
Boyd, John E.
A document describes the Interplanetary Overlay Networking Protocol Accelerator (IONAC) an electronic apparatus, now under development, for relaying data at high rates in spacecraft and interplanetary radio-communication systems utilizing a delay-tolerant networking protocol. The protocol includes provisions for transmission and reception of data in bundles (essentially, messages), transfer of custody of a bundle to a recipient relay station at each step of a relay, and return receipts. Because of limitations on energy resources available for such relays, data rates attainable in a conventional software implementation of the protocol are lower than those needed, at any given reasonable energy-consumption rate. Therefore, a main goal in developing the IONAC is to reduce the energy consumption by an order of magnitude and the data-throughput capability by two orders of magnitude. The IONAC prototype is a field-programmable gate array that serves as a reconfigurable hybrid (hardware/ firmware) system for implementation of the protocol. The prototype can decode 108,000 bundles per second and encode 100,000 bundles per second. It includes a bundle-cache static randomaccess memory that enables maintenance of a throughput of 2.7Gb/s, and an Ethernet convergence layer that supports a duplex throughput of 1Gb/s.
Pang, Jackson; Torgerson, Jordan L.; Clare, Loren P.
The rapid growth of video data leads to an urgent demand for efficient and true contentbased browsing and retrieving systems. In response to such needs, various video content analysis schemes using one or a combination of image, audio, and text information in videos have been proposed to parse, index, or abstract massive amount of data text in video is a very compact and accurate clue for video indexing and summarization. Most video text detection and extraction methods hold assumptions on text color, background contrast, and font style. Moreover, few methods can handle multilingual text well since different languages may have quite different appearances. In this paper, an efficient overlay text detection and extraction method is implemented which deals with complex backgrounds. Based on our observation that there exist transient colors between inserted text and its adjacent background. It is robust with respect to font size, style text, color, orientation and noise and can be used in a large variety of application fields such as mobile robot navigation vehicle license detection and recognition, object identification , document retrieving, etc.
Manohar, K.; Irfan, S.; Sravani, K.
Long-term ecological monitoring requires consistent observation of key variables, long-term measurement continuity, and open and affordable access to measurements. The Landsat series of Earth observation missions uniquely meet those criteria, and Landsat's 30m-observation scale permits the detection and differentiation of natural versus human-caused land change. Landsat is the longest and most comprehensive record of the state of the global land surface in existence. No other high-resolution satellite program is either capable or committed to the systematic monitoring of global scale human and natural land change. Beginning with Landsat 1 in 1972, six Landsat missions have continuously recorded images of the Earth. As we near the fortieth anniversary of Landsat, we now have an archive of millions of repetitive images of the Earth with multispectral properties suited to assessing both biotic and abiotic conditions and at a scale appropriate for resource management. The U.S. Geological Survey's (USGS) Earth Resources Observations Systems (EROS) Landsat archive contains nearly three million scenes and all are available to users at no cost. Furthermore, the entire Landsat record, Landsats 1-7, is now calibrated to a common radiometric standard and the majority of the data are orthorectified - enabling immediate assessment of long-term ecological conditions and land change. Landsats 5 and 7 continue to collect imagery and together they provide the potential to cover a significant portion of the Earth's land surfaces every eight days. Both of these missions now use a long-term acquisition plan designed to improve the collection of seasonal global coverage. Furthermore, recent agreements with international Landsat receiving stations are bringing previously inaccessible contemporary Landsat 5 data into the EROS archive. The amount of global coverage being acquired annually is the highest level in the history of the Landsat program. The EROS global historical archive is rapidly expanding because of the addition of 1972-present Landsat holdings from ground stations worldwide. More than three million Landsat scenes not currently found in the EROS archive exist in archives around the world and many of these data are at risk due to aging storage media and inadequate preservation practices. The repatriation of these data into the EROS archive will potentially double the number of no-cost Landsat scenes available to users. The uncertainty of future Landsat missions has challenged operational monitoring of ecological systems. However, that may be changing. The Landsat Data Continuity Mission (LDCM) being developed by NASA and the USGS is slated for a December 2012 launch. LDCM (which will be renamed Landsat 8 following launch) will use new imaging technology to provide improved multispectral measurements, and offers additional spectral bands and increased daily imaging capacity. While missions beyond LDCM are uncertain, the President's Fiscal Year 2012 budget requests funds for the planning and development of Landsats 9 and 10, and includes language that will make Landsat an operational program - ending the decades of uncertainty.
Loveland, T. R.
The non-U. S. Standard Catalog lists non-U. S. imagery acquired by LANDSAT 1 and 2 which has been processed and input to the data files during the referenced month. Data, such as date acquired, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found is also given.
The LANDSAT operations from launch through orbital instrument observations are reviewed. Orbital parameters, power subsystem, attitude control subsystem, and command/clock subsystem are discussed. Other subsystems are also considered, such as telemetry, orbit adjust, electrical interface, thermal, wideband telemetry, multispectral scanner, and data collection.
Performance analyses for LANDSAT 1 and 2, launched respectively in 1972 and 1975, are reported. Operational controls are evaluated, as well as orbital parameters and various subsystems. Both satellites continue to perform their missions normally, in spite of past minor operational malfunctions.
The LANDSAT-1 spacecraft was launched from the Western Test Range on 23 July 1972, at 18:08:06.508Z. The launch and orbital injection phase of the space flight was nominal, and deployment of the spacecraft followed predictions. Performance evaluation of the spacecraft is presented.
The U. S. standard catalog lists U. S. imagery acquired by LANDSAT 1 and 2 which has been processed and input to the data files during the referenced month. Data, such as date acquired, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found is also given.
A coordinated effort on the part of several agencies has led to the specification of a definitive radiometric calibration record for the Landsat-5 thematic mapper (TM) for its lifetime since launch in 1984. The time-dependent calibration record for Landsat-5 TM has been placed on the same radiometric scale as the Landsat-7 enhanced thematic mapper plus (ETM+). It has been implemented in the National Landsat Archive Production Systems (NLAPS) in use in North America. This paper documents the results of this collaborative effort and the specifications for the related calibration processing algorithms. The specifications include (i) anchoring of the Landsat-5 TM calibration record to the Landsat-7 ETM+ absolute radiometric calibration, (ii) new time-dependent calibration processing equations and procedures applicable to raw Landsat-5 TM data, and (iii) algorithms for recalibration computations applicable to some of the existing processed datasets in the North American context. The cross-calibration between Landsat-5 TM and Landsat-7 ETM+ was achieved using image pairs from the tandem-orbit configuration period that was programmed early in the Laridsat-7 mission. The time-dependent calibration for Landsat-5 TM is based on a detailed trend analysis of data from the on-board internal calibrator. The new lifetime radiometric calibration record for Landsat-5 will overcome problems with earlier product generation owing to inadequate maintenance and documentation of the calibration over time and will facilitate the quantitative examination of a continuous, near-global dataset at 30-m scale that spans almost two decades.
Teillet, P.M.; Helder, D.L.; Ruggles, T.A.; Landry, R.; Ahern, F.J.; Higgs, N.J.; Barsi, J.; Chander, G.; Markham, B.L.; Barker, J.L.; Thome, K.J.; Schott, J.R.; Palluconi, F.D.
The CASA (Carnegie Ames Stanford Approach) ecosystem process model predicts terrestrial ecosystem fluxes using satellite-based inputs at a maximum geographic resolution of 30 meters to infer variability in forest carbon fluxes. We are using CASA to model pine plantation net ecosystem production (NEP) under a range of standard silvicultural prescriptions, primarily thinning by fertilization interactions. Landsat scenes from WRS path/row 14/35, 21/37, and 16/34 are being used. Within each frame, all available cloud-free scenes within a two- to three-year period have been obtained from the USGS EROS Data Center processed to L1T, and subsequently converted to top-of-atmosphere reflectance using standard methods and the latest calibration parameter files. Atmospheric amelioration started with dark object subtraction (band minimum) and only proceeded to more complex techniques as necessary. Subsequent to preprocessing, the reduced simple ratio (RSR; using global min/max) was calculated for all images for each WRS path/row. Pure pine pixels in each frame were identified using unsupervised classification of the most recent leaf-off scene. We developed four age classes using two decades of Landsat data over each WRS path/row. CASA runs, which require soil parameters, and gridded climate/solar radiation in addition to satellite-derived vegetation indices, are now complete. Soil respiration and productivity estimates are being evaluated using a regionwide network of validation sites spanning the range of loblolly pine (Texas to Virginia). Preliminary results indicate that Landsat-based process modeling (1) is necessary for the scale at which land is actually managed and (2) produces estimates with an accuracy and precision affording improved understanding and management of forest ecosystems.
Wynne, R. H.; Potter, C. S.; Blinn, C. E.
The U.S. Standard Catalog lists U.S. imagery acquired by LANDSAT 1 and LANDSAT 2 which las been processed and input to the data files during the referenced month. Data, such as date acquired, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found is also given.
for Remote Sensing Publisher: Natural Resources Canada, Government of Canada Edition: N/A Versions: N Geogratis-Landsat 7 Orthorectified Citation: Canada Centre for Remote Sensing. "Landsat 7 Orthorectified Management, Forest Mensuration, Forest Commodities, Forest Protection, Forest Yield, Reforestation, Land Use
An illumination correction algorithm has been developed to improve the accuracy of forest change detection from Landsat reflectance data. This algorithm is based on an empirical rotation model and was tested on the Landsat imagery pair over Cherokee National Forest, Tennessee, Uinta-Wasatch-Cache N...
Research and development on atmospheric and topographic correction methods for multispectral satellite data such as Landsat images has far outpaced the availability of those methods in Geographic Information Systems software. As Landsat and other data become more widely available, demand for these i...
FOR IMAGING SCIENCE Title of Dissertation: Demonstrating Landsat's New Potential to Monitor Coastal and InlandDemonstrating Landsat's New Potential to Monitor Coastal and Inland Waters by Aaron Gerace B Center for Imaging Science Rochester Institute of Technology May 2010 Signature of the Author Accepted
The U.S. standard catalog lists U.S. imagery acquired by LANDSAT 1 and LANDSAT 2 which has been processed and input to the data files during the referenced month. Data, such as date acquired, cloud cover and image quality are given for each scene. The microfilm and frame on which the scene may be found is also given.
The U.S. Standard Catalog lists U.S. imagery acquired by LANDSAT 1 and LANDSAT 2 which has been processed and input to the data files during the referenced month. Data, such as date acquired, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found is also given.
The LANDSAT 1 U.S. Cumulative Catalog lists U.S. imagery acquired by LANDSAT 1 which has been processed and input to the data files during the referenced year. Data, such as data acquired, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found are also given.
Collection of ground information and supportive materials are absolutely necessary to verify and substantiate data extracted by the interpretation process regardless of sensor type and scale. Field observation and notes, the use of topographic and thematic maps, crop calendars, and climate records are just four examples of supportive materials which often are used in conjunction with remotely sensed materials. Illustration of this integrated multisensor approach is provided by four examples from the March, 1978 Santa Maria LANDSAT C Conference and Workshop. Four distinctive window sites were selected to demonstrate the usefulness of remotely sensed materials to solve geographic problems.
Frasca, J. W.
The author has identified the following significant results. LANDSAT imageries of Mirpur area of Dacca district were used in connection with surveys for black plastic clay. The imageries showed the broad pattern of small valleys cutting into Madhupur clay. Land use maps of Haor areas of Sylhet and Mymensingh districts were prepared. As a test case, two thana areas, namely Nickley and Astogram, were classified in different categories such as crop, settlement, and water. It does not show much agreement with the Agriculture Dept.'s statistics.
Hossain, A. (principal investigator)
A unified package of files and programs has been developed to automate the multidate Landsat-derived analyses of water quality for about 3000 inland lakes throughout Wisconsin. A master lakes file which stores geographic information on the lakes, a file giving the latitudes and longitudes of control points for scene navigation, and a program to estimate control point locations and produce microfiche character maps for scene navigation are among the files and programs of the system. The use of ground coordinate systems to isolate irregular shaped areas which can be accessed at will appears to provide an economical means of restricting the size of the data set.
Fisher, L. T.; Scarpace, F. L.; Thomsen, R. G.
The authors have identified the following significant results. By using suspended sediments as tracers, objectives were met by qualitative definition of the nearshore circulation along the entire coast of California with special study sites at Humboldt Bay, the mouth of the Russian River, San Francisco Bay, Monterey Bay, and the Santa Barbara Channel. Although LANDSAT primarily imaged fines and silts in the surface waters, the distribution of sediments allowed an examination of upwelling, convergences and coastal erosion and deposition. In Monterey Bay and Humboldt Bay, these coastal phenomena were used to trace seasonal trends in surface currents.
Pirie, D. M.; Steller, D. D. (principal investigators)
Applications of Landsat data in hydrology and water quality measurement were examined to determine which applications are operational. In hydrology, the principal applications have been surface water inventory, and land cover analysis for (1) runoff modeling and (2) abatement planning for non-point pollution and erosion. In water quality measurement, the principal applications have been: (1) trophic state assessment, and (2) measurement of turbidity and suspended sediment. The following applications were found to be operational: mapping of surface water, snow cover, and land cover (USGS Level 1) for watershed applications; measurement of turbidity, Secchi disk depth, suspended sediment concentration, and water depth.
Middleton, E. M.; Munday, J. C., Jr.
The radiometric integrity of the LANDSAT-D thematic mapper (TM) thermal infrared channel (band 6) data was evaluated to develop improved radiometric preprocessing calibration techniques for removal of atmospheric effects. Primary data analysis was spent in evaluating the line to line and detector to detector variation in the thermal infrared data. The data studied was in the core area of Lake Ontario where very stable temperatures were expected. The detectors and the scan direction were taken as separate parameters and an analysis of variance was conducted. The data indicate that significant variability exists both between detectors and between scan directions.
Monitoring of water bodies from satellite platforms has been a subject of much interest from the operational point of view. However, computing lake surface area for estimating water volumes would have limited applicability in areas of high topographic relief. Therefore, a method is offered, involving marking of land-water contact from satellite data along low-gradient channels. The applicability of the method has been tested on the Ramganga dam reservoir (Himalayas, India) using Landsat MSS CCT's, field spectro-radiometric measurements and theodolite surveys. It is considered that the technique can be utilized in areas of known topography for real-time remote monitoring of fluctuations in reservoir volume.
Gupta, R. P.; Banerji, S.
In the project described remote sensing was used to check the quality of lake waters. The lakes of three Landsat scenes were mapped with the Bendix MDAS multispectral analysis system. From the MDAS color coded maps, the lake with the worst algae problem was easily located. The lake was closely checked, and the presence of 100 cows in the springs which fed the lake could be identified as the pollution source. The laboratory and field work involved in the lake classification project is described.
Scherz, J. P.
The Interplanetary Overlay Network (ION) system's BP package, an implementation of the Delay-Tolerant Networking (DTN) Bundle Protocol (BP) and supporting services, has been specifically designed to be suitable for use on deep-space robotic vehicles. Although the ION BP implementation is unique in its use of zero-copy objects for high performance, and in its use of resource-sensitive rate control, it is fully interoperable with other implementations of the BP specification (Internet RFC 5050). The ION BP implementation is built using the same software infrastructure that underlies the implementation of the CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol (CFDP) built into the flight software of Deep Impact. It is designed to minimize resource consumption, while maximizing operational robustness. For example, no dynamic allocation of system memory is required. Like all the other ION packages, ION's BP implementation is designed to port readily between Linux and Solaris (for easy development and for ground system operations) and VxWorks (for flight systems operations). The exact same source code is exercised in both environments. Initially included in the ION BP implementations are the following: libraries of functions used in constructing bundle forwarders and convergence-layer (CL) input and output adapters; a simple prototype bundle forwarder and associated CL adapters designed to run over an IPbased local area network; administrative tools for managing a simple DTN infrastructure built from these components; a background daemon process that silently destroys bundles whose time-to-live intervals have expired; a library of functions exposed to applications, enabling them to issue and receive data encapsulated in DTN bundles; and some simple applications that can be used for system checkout and benchmarking.
Burleigh, Scott C.
It has been found that flood boundary information derived from Landsat images, acquired at different flood stages, could be used to develop an empirical model for estimating the extent of flooding on the basis of in situ measurements of river discharge. An investigation was undertaken to determine whether improved results might have been obtained through digital image analysis or by including other Landsat spectral bands. The study area encompasses a highly flood-prone reach of the Black River in Lewis County, NY. It was found that visual analysis of aerial photographs and a Landsat band 7 image gave similar results. Visual and digital analysis of Landsat band 7 data gave similar results, and digital analysis of Landsat band 7 data gave results which were at least as good as digital analysis of combinations of spectral bands.
Philipson, W. R.; Hafker, W. R.
The launch data of LANDSAT 3 is announced. The improved capability of the spacecrafts' remote sensors (the return beam vidicon and the multispectral scanner) and application of LANDSAT data to the study of energy supplies, food production, and global large-scale environmental monitoring are discussed along with the piggyback amateur radio communication satellite-OSCAR-D, the plasma Interaction Experiment, and the data collection system onboard LANDSAT 3. An assessment of the utility of LANDSAT multispectral data is given based on the research results to data from studies of LANDSAT 1 and 2 data. Areas studied include agriculture, rangelands, forestry, water resources, environmental and marine resources, environmental and marine resources, cartography, land use, demography, and geological surveys and mineral/petroleum exploration.
A simulation of imagery from the upcoming LANDSAT-D thematic mapper was accomplished by using selected channels of 24-channels aircraft multispectral scanner data. The purpose was to simulate thematic mapper 30-meter resolution imagery and compare its spectral quality with the original aircraft MSS data and determine changes in thematic classification accuracy for the simulated imagery. The original resolution of approximately 7.5 meters IFOV and simulated resolution of 15, 30, and 60 meters were used to indicate the trend of spectral quality and classification accuracy. The study was based in a 6.5 square kilometer area of urban Los Angeles having a diversity of land use.
Clark, J.; Bryant, N. A.
Initiated in 1972, the Landsat program has provided a continuous record of earth observation for 35??years. The assemblage of Landsat spatial, spectral, and temporal resolutions, over a reasonably sized image extent, results in imagery that can be processed to represent land cover over large areas with an amount of spatial detail that is absolutely unique and indispensable for monitoring, management, and scientific activities. Recent technical problems with the two existing Landsat satellites, and delays in the development and launch of a successor, increase the likelihood that a gap in Landsat continuity may occur. In this communication, we identify the key features of the Landsat program that have resulted in the extensive use of Landsat data for large area land cover mapping and monitoring. We then augment this list of key features by examining the data needs of existing large area land cover monitoring programs. Subsequently, we use this list as a basis for reviewing the current constellation of earth observation satellites to identify potential alternative data sources for large area land cover applications. Notions of a virtual constellation of satellites to meet large area land cover mapping and monitoring needs are also presented. Finally, research priorities that would facilitate the integration of these alternative data sources into existing large area land cover monitoring programs are identified. Continuity of the Landsat program and the measurements provided are critical for scientific, environmental, economic, and social purposes. It is difficult to overstate the importance of Landsat; there are no other systems in orbit, or planned for launch in the short-term, that can duplicate or approach replication, of the measurements and information conferred by Landsat. While technical and political options are being pursued, there is no satellite image data stream poised to enter the National Satellite Land Remote Sensing Data Archive should system failures occur to Landsat-5 and -7. Crown Copyright ?? 2007.
Wulder, M.A.; White, J.C.; Goward, S.N.; Masek, J.G.; Irons, J.R.; Herold, M.; Cohen, W.B.; Loveland, T.R.; Woodcock, C.E.
The U.S. Standard Catalog lists U.S. imagery acquired by LANDSAT 1 and LANDSAT 2 which has been processed and input to the data files during the referenced month. Data, such as data acquired, cloud cover and image quality are given for each scene. The microfilm roll and frame on which the scene may be found is also given.
This paper discusses the development and implementation of a geospatial data processing method and multi-decadal Landsat time series for computing general coastal U.S. land-use and land-cover (LULC) classifications and change products consisting of seven classes (water, barren, upland herbaceous, non-woody wetland, woody upland, woody wetland, and urban). Use of this approach extends the observational period of the NOAA-generated Coastal Change and Analysis Program (C-CAP) products by almost two decades, assuming the availability of one cloud free Landsat scene from any season for each targeted year. The Mobile Bay region in Alabama was used as a study area to develop, demonstrate, and validate the method that was applied to derive LULC products for nine dates at approximate five year intervals across a 34-year time span, using single dates of data for each classification in which forests were either leaf-on, leaf-off, or mixed senescent conditions. Classifications were computed and refined using decision rules in conjunction with unsupervised classification of Landsat data and C-CAP value-added products. Each classification's overall accuracy was assessed by comparing stratified random locations to available reference data, including higher spatial resolution satellite and aerial imagery, field survey data, and raw Landsat RGBs. Overall classification accuracies ranged from 83 to 91% with overall Kappa statistics ranging from 0.78 to 0.89. The accuracies are comparable to those from similar, generalized LULC products derived from C-CAP data. The Landsat MSS-based LULC product accuracies are similar to those from Landsat TM or ETM+ data. Accurate classifications were computed for all nine dates, yielding effective results regardless of season. This classification method yielded products that were used to compute LULC change products via additive GIS overlay techniques.
Spruce, J. P.; Smoot, James; Ellis, Jean; Hilbert, Kent; Swann, Roberta
The newly emerging lithographic technologies related to the 32nm node and below will require a step function in the overlay metrology performance, due to the dramatic shrinking of the error budgets. In this work, we present results of an emerging alternative technology for overlay metrology - Differential signal scatterometry overlay (SCO TM). The technique is based on spectroscopic analysis of polarized light, reflected from a "grating-on-grating" target. Based on theoretical analysis and initial data, this technology, as well as broad band bright field overlay, is a candidate technology that will allow achieving the requirements of the 32nm node and beyond it. We investigate the capability of SCOL TM to control overlay in a production environment, on complex stacks and process, in the context of advanced DRAM and Flash technologies. We evaluate several metrology mark designs and the effect on the metrology performance, in view of the tight TMU requirements of the 32nm node. The results - achieved on the KLA-Tencor's Archer tool, equipped with both broad band bright field AIM TM and scatterometry SCOL TM sensors - indicate the capability of the SCOL TM technology to satisfy the advanced nodes requirements.
Dinu, Berta; Fuchs, Stefan; Kramer, Uwe; Kubis, Michael; Marchelli, Anat; Navarra, Alessandra; Sparka, Christian; Widmann, Amir
An image registration system has been developed at the NASA Johnson Space Center (JSC) to spatially align multi-temporal Landsat acquisitions for use in agriculture and forestry research. Working in conjunction with the Master Data Processor (MDP) at the Goddard Space Flight Center, it functionally replaces the long-standing LACIE Registration Processor as JSC's data supplier. The system represents an expansion of the techniques developed for the MDP and LACIE Registration Processor, and it utilizes the experience gained in an IBM/JSC effort evaluating the performance of the latter. These techniques are discussed in detail. Several tests were developed to evaluate the registration performance of the system. The results indicate that 1/15-pixel accuracy (about 4m for Landsat MSS) is achievable in ideal circumstances, sub-pixel accuracy (often to 0.2 pixel or better) was attained on a representative set of U.S. acquisitions, and a success rate commensurate with the LACIE Registration Processor was realized. The system has been employed in a production mode on U.S. and foreign data, and a performance similar to the earlier tests has been noted.
Wolfe, R. H., Jr.; Juday, R. D.; Wacker, A. G.; Kaneko, T.
The Landsat Data Continuity Mission (LDCM) is on schedule for a December 2012 launch date. The mission is being managed by an interagency partnership between NASA and the U.S. Geological Survey (USGS). NASA leads the development and launch of the satellite observatory while leads ground system development. USGS will assume responsibility for operating the satellite and for collecting, archiving, and distributing the LDCM data following launch. When launched the satellite will carry two sensors into orbit. The Operational Land Imager (OLI) will collect data for nine shortwave spectral bands with a spatial resolution of 30 m (with a 15 m panchromatic band). The Thermal Infrared Sensor (TIRS) will coincidently collect data for two thermal infrared bands with a spatial resolution of 100 m. The OLI is fully assembled and tested and has been shipped by it?s manufacturer, Ball Aerospace and Technology Corporation, to the Orbital Sciences Corporation (Orbital) facility where it is being integrated onto the LDCM spacecraft. Pre-launch testing indicates that OLI will meet all performance specification with margin. TIRS is in development at the NASA Goddard Space Flight Center (GSFC) and is in final testing before shipping to the Orbital facility in January, 2012. The ground data processing system is in development at the USGS Earth Resources Observation and Science (EROS) Center. The presentation will describe the LDCM satellite system, provide the status of system development, and present prelaunch performance data for OLI and TIRS. The USGS has committed to renaming the satellite as Landsat 8 following launch.
Irons, Jim; Sabelhaus, Phil; Masek, Jeff; Cook, Bruce; Dabney, Phil; Loveland, Tom
Work undertaken during the contract and its results are described. Many of the results from this investigation are available in journal or conference proceedings literature - published, accepted for publication, or submitted for publication. For these the reference and the abstract are given. Those results that have not yet been submitted separately for publication are described in detail. Accomplishments during the contract period are summarized as follows: (1) analysis of the snow reflectance characteristics of the LANDSAT Thematic Mapper, including spectral suitability, dynamic range, and spectral resolution; (2) development of a variety of atmospheric models for use with LANDSAT Thematic Mapper data. These include a simple but fast two-stream approximation for inhomogeneous atmospheres over irregular surfaces, and a doubling model for calculation of the angular distribution of spectral radiance at any level in an plane-parallel atmosphere; (3) incorporation of digital elevation data into the atmospheric models and into the analysis of the satellite data; and (4) textural analysis of the spatial distribution of snow cover.
Dozier, J. (principal investigator); Davis, R. E.; Dubayah, R. O.; Frew, J. E.; Li, S.; Marks, D.; Milliff, R. F.; Rousseau, D. D.; Wan, Z. M.
The radiometric data quality of the LANDSAT 4 multispectral scanner (MSS) was examined using several LANDSAT 4 frames. It was found that LANDSAT 4 MSS produces high-quality data of the caliber experienced with previous LANDSATS. For example, the detector equalization procedure worked well, leaving a residual banding effect of about 0.3 digital counts RMS, close to the theoretical minimum value of quantization error. Nevertheless, artifacts of the data were found, two of which were not experienced in previous MSS data. A low-level coherent noise effect was observed in all bands, with a magnitude of about 0.5 digital counts and a frequency of approximately 28 KHz (representing a wavelength of about 3.6 pixels); a substantial increase in processing complexity would be required to reduce this artifact in the data. Also, a substantial scan-length variation (of up to six pixels) was noted in MSS data when the TM sensor was operating; the LANDSAT 4 correction algorithms being applied routinely by the EROS Data Center to produce a p-type data should remove most of this variation. Between-satellite calibrations were examined in paired LANDSAT 3 and LANDSAT 4 MSS data sets, which were closely matched in acquisition time and place. Radiometric comparisons showed that all bands were highly linear in digital counts, and a well-determined linear transformation between the MSS's was established.
Malila, W. A. (principal investigator); Rice, D. P.
services, operational management becomes exceedingly important and challenging (and thus interestingWEB SERVICES MANAGEMENT NETWORK An Overlay Network for Federated Service Management Vijay Machiraju, and protocols of a management overlay for federated service management, called Web Services Management Network
Newcastle upon Tyne, University of
Simplified Solution for Periodic Thermal Discontinuities in Asphalt Overlays Bonded to Rigid discontinuities distributed in a hot mix asphalt overlay bonded to a rigid pavement, where the length Database subject headings: Thermal stresses; Fracture mechanics; Asphalt pavements; Rigid pavements
Paulino, Glaucio H.
We perform a theoretical study of the nonreciprocal reflection of high-frequency microwave radiation from ferromagnetic films with thin overlayers. Reflection from metallic ferromagnetic films is always near unity and shows no nonreciprocity. In contrast, reflection from a structure which has a dielectric overlayer on top of a film composed of insulated ferromagnetic nanoparticles or nanostructures can show significant nonreciprocity in the 75–80?GHz frequency range, a very high value. This can be important for devices such as isolators or circulators.
Wang, Ying; Nie, Yan; Camley, R. E. [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, Colorado Springs, Colorado 80918 (United States)
Since January 2008, the U.S. Department of Interior \\/ U.S. Geological Survey have been providing free terrain-corrected (Level 1T) Landsat Enhanced Thematic Mapper Plus (ETM+) data via the Internet, currently for acquisitions with less than 40% cloud cover. With this rich dataset, temporally composited, mosaics of the conterminous United States (CONUS) were generated on a monthly, seasonal, and annual basis
David P. Roy; Junchang Ju; Kristi Kline; Pasquale L. Scaramuzza; Valeriy Kovalskyy; Matthew Hansen; Thomas R. Loveland; Eric Vermote; Chunsun Zhang
Application-layer multicast (ALM) protocols differ in, among other aspects, the topology of the underlying overlay network (e.g., tree, mesh or ring). Therefore, comparing the performance of ALM overlay networks is an important step to- wards assessing the inherent advantages and\\/or limitations of each overlay network topology. In particular, ring-based ALM overlay networks have the advantages of (a) providing a con-
Ahmed Sobeih; Jun Wang; William Yurcik
An improved overlay mark design was applied in high end semiconductor manufacturing to increase the total overlay measurement accuracy with respect to the standard box-in-box target. A comprehensive study has been conducted on the basis of selected front-end and back-end DRAM layers (short loop) to characterize contributors to overlay error. This analysis is necessary to keep within shrinking overlay budget requirements.
Gruss, Stefan; Teipel, Ansgar; Fuelber, Carsten; Kassel, Elyakim; Adel, Mike; Ghinovker, Mark; Izikson, Pavel
The comparative value of manual versus digital image analysis for determining flood boundaries is being examined in a study of the use of Landsat data for modeling flooding of the Black River, in northern New York. The work is an extension of an earlier study in which Black River flooding was assessed through visually interpreted, multi-date Landsat band 7 images. Based on the results to date, it appears that neither color-additive viewing nor digital analysis of Landsat data provide improvement in accuracy over visual analysis of band 7 images, for delineating the boundaries of flood-affected areas.
Philipson, W. R.; Hafker, W. R.
Surface reflectance adjusted for atmospheric effects is a primary input for land cover change detection and for developing many higher level surface geophysical parameters. With the development of automated atmospheric correction algorithms, it is now feasible to produce large quantities of surface reflectance products using Landsat images. Validation of these products requires in situ measurements, which either do not exist or are difficult to obtain for most Landsat images. The surface reflectance products derived using data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), however, have been validated more comprehensively. Because the MODIS on the Terra platform and the Landsat 7 are only half an hour apart following the same orbit, and each of the 6 Landsat spectral bands overlaps with a MODIS band, good agreements between MODIS and Landsat surface reflectance values can be considered indicators of the reliability of the Landsat products, while disagreements may suggest potential quality problems that need to be further investigated. Here we develop a system called Landsat-MODIS Consistency Checking System (LMCCS). This system automatically matches Landsat data with MODIS observations acquired on the same date over the same locations and uses them to calculate a set of agreement metrics. To maximize its portability, Java and open-source libraries were used in developing this system, and object-oriented programming (OOP) principles were followed to make it more flexible for future expansion. As a highly automated system designed to run as a stand-alone package or as a component of other Landsat data processing systems, this system can be used to assess the quality of essentially every Landsat surface reflectance image where spatially and temporally matching MODIS data are available. The effectiveness of this system was demonstrated using it to assess preliminary surface reflectance products derived using the Global Land Survey (GLS) Landsat images for the 2000 epoch. As surface reflectance likely will be a standard product for future Landsat missions, the approach developed in this study can be adapted as an operational quality assessment system for those missions.
Feng, Min; Huang, Chengquan; Channan, Saurabh; Vermote, Eric F.; Masek, Jeffrey G.; Townshend, John R.
Surface reflectance adjusted for atmospheric effects is a primary input for land cover change detection and for developing many higher level surface geophysical parameters. With the development of automated atmospheric correction algorithms, it is now feasible to produce large quantities of surface reflectance products using Landsat images. Validation of these products requires in situ measurements, which either do not exist or are difficult to obtain for most Landsat images. The surface reflectance products derived using data acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS), however, have been validated more comprehensively. Because the MODIS on the Terra platform and the Landsat 7 are only half an hour apart following the same orbit, and each of the 6 Landsat spectral bands overlaps with a MODIS band, good agreements between MODIS and Landsat surface reflectance values can be considered indicators of the reliability of the Landsat products, while disagreements may suggest potential quality problems that need to be further investigated. Here we develop a system called Landsat-MODIS Consistency Checking System (LMCCS). This system automatically matches Landsat data with MODIS observations acquired on the same date over the same locations and uses them to calculate a set of agreement metrics. To maximize its portability, Java and open-source libraries were used in developing this system, and object-oriented programming (OOP) principles were followed to make it more flexible for future expansion. As a highly automated system designed to run as a stand-alone package or as a component of other Landsat data processing systems, this system can be used to assess the quality of essentially every Landsat surface reflectance image where spatially and temporally matching MODIS data are available. The effectiveness of this system was demonstrated using it to assess preliminary surface reflectance products derived using the Global Land Survey (GLS) Landsat images for the 2000 epoch. As surface reflectance likely will be a standard product for future Landsat missions, the approach developed in this study can be adapted as an operational quality assessment system for those missions.
Feng, Min; Huang, Chengquan; Channan, Saurabh; Vermote, Eric; Masek, Jeffrey G.; Townshend, John R.
Detailed thermal models of the LANDSAT-D Earth Sensor Assembly Module (ESAM), the Dummy Thematic Mapper (DTM), and a small thermal model of the LANDSAT-D spacecraft for a heater analysis were developed. These models were used to develop and verify the thermal design of the ESAM and DTM, to evaluate the aeroheating effects on ESAM during launch and to evaluate the thermal response of the LANDSAT-D assuming the hard-line heaters failed on with the spacecraft in the Space Transportation System (STS) orbiter bay. Results of model applications are summarized.
Activities are provided for: (1) developing insight into the way in which the LANDSAT MSS produces multispectral data; (2) promoting understanding of what a "pixel" means in a LANDSAT image and the implications of the term "mixed pixel"; (3) explaining the concept of spectral signatures; (4) deriving a simple signature for a class or feature by analysis: of the four band images; (5) understanding the production of false color composites; (6) appreciating the use of color additive techniques; (7) preparing Diazo images; and (8) making quick visual identifications of major land cover types by their characteristic gray tones or colors in LANDSAT images.
The Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) software was originally developed by the National Aeronautics and Space Administration–Goddard Space Flight Center and the University of Maryland to produce top-of-atmosphere reflectance from LandsatThematic Mapper and Enhanced Thematic Mapper Plus Level 1 digital numbers and to apply atmospheric corrections to generate a surface-reflectance product.The U.S. Geological Survey (USGS) has adopted the LEDAPS algorithm for producing the Landsat Surface Reflectance Climate Data Record.This report discusses the LEDAPS algorithm, which was implemented by the USGS.
Schmidt, Gail; Jenkerson, Calli; Masek, Jeffrey; Vermote, Eric; Gao, Feng
A method is described for making an estimate of wetland numbers in the glaciated prairie region. A double-phase sampling approach is used which consists of first making a total census of wetlands using Landsat data, and then adjusting the Landsat results on the basis of samples derived from high resolution aircraft data. The method is relatively simple to use and has general applicability for estimating habitat features not consistently detectable or resolvable on Landsat imagery because their size range includes features less than the resolution capability of the satellite's sensor.
Gilmer, D.S.; Work, E.A., Jr.; Colwell, J.E.; Rebel, D.L.
The geometric accuracy of the Landsat Thematic Mappers was assessed by a linear least-square comparison of the positions of conspicuous ground features in digital images with their geographic locations as determined from 1:24 000-scale maps. For a Landsat-5 image, the single-dimension standard deviations of the standard digital product, and of this image with additional linear corrections, are 11.2 and 10.3 m, respectively (0.4 pixel). An F-test showed that skew and affine distortion corrections are not significant. At this level of accuracy, the granularity of the digital image and the probable inaccuracy of the 1:24 000 maps began to affect the precision of the comparison. The tested image, even with a moderate accuracy loss in the digital-to-graphic conversion, meets National Horizontal Map Accuracy standards for scales of 1:100 000 and smaller. Two Landsat-4 images, obtained with the Multispectral Scanner on and off, and processed by an interim software system, contain significant skew and affine distortions. -Authors
Borgeson, W.T.; Batson, R.M.; Kieffer, H.H.
Pavement systems have significant impacts on the environment and economy due to large material consumption, energy input, and capital investment. To evaluate the sustainability of rigid pavement overlay designs, an integrated life cycle assessment and life cycle cost analysis model was developed to calculate the environmental impacts and costs of overlay systems resulting from material production and distribution, overlay construction
H. Zhang; G. A. Keoleian; M. D. Lepech
RESEARCH REPORT 987-9 ASPHALT OVERLAY DESIGN METHODS FOR RIGID PAVEMENTS CONSIDERING RUTTING's Catalog No. 5. Report Date October 1998 4. Title and Subtitle ASPHALT OVERLAY DESIGN METHODS FOR RIGID of this study were (1) to provide basic performance evaluation of asphalt overlays on rigid pavements and (2
Texas at Austin, University of
As fabs transition from 200 to 300mm wafers with shrinking design rules, the risk and cost associated with overlay excursions become more severe. This significantly impacts the overall litho-cell efficiency. Effective detection, identification, and reduction of overlay excursions are essential for realizing the productivity and cost benefits of the technology shifts. We have developed a comprehensive overlay excursion management method
Xuemei Chen; Ming-Yeon Hung; Kelly Kuo; Steven Fu; Geoge Shanthikumar; Zhoujie Mao; Shiming Deng; Viral Hazari; Kevin M. Monahan; Mike D. Slessor; Amir Lev
A research program to measure the LANDSAT 4 Thematic Mapper (TM) modulation transfer function (MTF) is described. Measurement of a satellite sensor's MTF requires the use of a calibrated ground target, i.e., the spatial radiance distribution of the target must be known to a resolution at least four to five times greater than that of the system under test. A small reflective mirror or a dark light linear pattern such as line or edge, and relatively high resolution underflight imagery are used to calibrate the target. A technique that utilizes an analytical model for the scene spatial frequency power spectrum will be investigated as an alternative to calibration of the scene. The test sites and analysis techniques are also described.
This paper presents an analysis of the flight data from a new design of horizon scanner flown on Landsat-4. The salient features in the data are described and demonstrated by data plots. High frequency noise must be filtered out to achieve good accuracy, but this is effectively done by 128-point averaging. Sun and moon interference effects are identified. The effects of earth oblateness and spacecraft altitude variations are modeled, and the residual systematic errors are analyzed. Most of the residual errors are apparently explained by the effects of earth radiance variation, with the winter polar regions showing the highest variability in the attitude measurements due to winter stratosphere temperature variations. In general, this sensor provides improved accuracy over those flown on previous missions.
Bilanow, S.; Chen, L. C.
The author has identified the following significant results. Visual and automatic interpretation of LANDSAT imagery was used to classify the general Pinus and Eucalyptus according to their age and species. A methodology was derived, based on training areas, to define the legend and spectral characteristics of the analyzed classes. Imager analysis of the training areas show that Pinus taeda is separable from the other Pinus species based on JM distance measurement. No difference of JM measurements was observed among Eucalyptus species. Two classes of Eucalyptus were separated according to their ages: those under and those over two years of age. Channel 6 and 7 were suitable for the discrimination of the reforested classes. Channel 5 was efficient to separated reforested areas from nonforested targets in the region. The automatic analysis shows the highest classification precision was obtained for Eucalyptus over two years of age (95.12 percent).
Dejesusparada, N. (principal investigator); Filho, P. H.; Shimabukuro, Y. E.
A periodic 3% to 5% variation in detector response affecting both image and internal calibrator (IC) data has been observed in bands 5 and 7 of the Landsat-5 Thematic Mapper. The source for this variation is thought to be an interference effect due to buildup of an ice-like contaminant film on a ZnSe window, covered with an antireflective coating (ARC), of the cooled dewar containing these detectors. Periodic warming of the dewar is required in order to remove the contaminant and restore detector response to an uncontaminated level. These effects in the IC data have been characterized over four individual outgassing cycles using thin-film models to estimate transmittance of the window/ARC and ARC/contaminant film stack throughout the instrument lifetime. Based on the results obtained from this modeling, a lookup table procedure has been implemented that provides correction factors to improve the calibration accuracy of bands 5 and 7 by approximately 5%.
Helder, D.L.; Micijevic, E.
The sample LANDSAT-4 TM tape (7 bands) of NE Arkansas/Tennessee area was received and displayed. Snow reflectance in all 6 TM reflective bands, i.e. 1, 2, 3, 4, 5, and 7 was simulated, using Wiscombe and Warren's (1980) delta-Eddington model. Snow reflectance in bands 4, 5, and 7 appear sensitive to grain size. One of the objectives is to interpret surface optical grain size of snow, for spectral extension of albedo. While TM data of the study area are not received, simulation results are encouraging. It also appears that the TM filters resemble a "square-wave" closely enough to permit assuming a square-wave in calculations. Integrated band reflectance over the actual response functions was simulated, using sensor data supplied by Santa Barbara Research Center. Differences between integrating over the actual response functions and the equivalent square wave were negligible.
Dozier, J. (principal investigator)
We investigated the surface properties of GaAs with thin (6 to 100 A) epitaxial Si layers grown by MBE (Molecular Beam Epitaxy). The results indicate that the GaAs surface potential, which is commonly pinned at around the center of the energy gap, can be varied over a wide range of positions in the GaAs gap. Schottky barrier structures grown in-situ in the MBE with Al as a contact metal and thin Si layers grown between Al and GaAs were shown to have near-ideal thermionic emission characteristics and effective barrier heights in the range 0.3
Costa, Julio Carlos
Environmental monitoring through the method of traditional ship sampling is time consuming and requires a high survey cost. The objective of this study is to evaluate the feasibility of Landsat TM imagery for total suspended solids (TSS) mapping using a newly developed algorithm over Penang Island. The study area is the seawater region around Penang Island, Malaysia. Water samples were collected during a 3-hour period simultaneously with the satellite image acquisition and later analyzed in the laboratory above the study area. The samples locations were determined using a handheld GPS. The satellite image was geometrically corrected using the second order polynomial transformation. The satellite image also was atmospheric corrected by using ATCOR2 image processing software. The digital numbers for each band corresponding to the sea-truth locations were extracted and then converted into reflectance values for calibration of the water quality algorithm. The proposed algorithm is based on the reflectance model that is a function of the inherent optical properties of water, which can be related to its constituent's concentrations. The generated algorithm was developed for three visible wavelenghts, red, green and blue for this study. Results indicate that the proposed developed algorithm was superior based on the correlation coefficient (R) and root-mean-square deviation (RMS) values. Finally the proposed algorithm was used for TSS mapping at Penang Island, Malaysia. The generated TSS map was colour-coded for visual interpretation and image smoothing was performed on the map to remove random noise. This preliminary study has produced a promising result. This study indicates that the empirical algorithm is suitable for TSS mapping around Penang Island by using satellite Landsat TM data.
Lim, H. S.; MatJafri, M. Z.; Abdullah, K.; Alias, A. N.; Wong, C. J.; Mustapha-Rosli, M. R.; Mohd Saleh, N.
I begin by introducing Virtual Design Apprenticeship (VDA), a learning model--built on a solid foundation of education principles and theories--that promotes learning of design skills via overlay design tools. In VDA, when an individual needs to learn a new design skill or paradigm she is provided accessible, concrete examples that have been…
Carle, Andrew Jacob
This experiment subjects bacteria in a food sample and an environmental sample to conditions of sublethal stress in order to assess the effectiveness of the agar overlay method to recover sublethally injured cells compared to direct plating onto the appropriate selective medium. (SAH)
McKillip, John L.
Multicast support is critical and a desirable feature of wireless mesh networks (WMNs). In this paper, we propose an approach to joint optimizing rate allocation of flows and power consumption of links for forwarding data flows for overlay multicast in WMNs. We develop a distributed algorithm based on pricing scheme by using dual decomposition technique. The \\
Cuitao Zhu; Di Wu; Wenqing Cheng; Zongkai Yang
, such as head-mounted displays [1,2], video projections , and volumetric image overlay  have been human trials. 2. SystemDesign A flat LCD display and a semi- transparent mirror are mounted placement in conventional CT scanners. The device consisting of a flat LCD display and a half mirror
Paris-Sud XI, UniversitÃ© de
T-Man: Gossip-based Overlay Topology Management MÂ´ark Jelasity and Ozalp Babaoglu University of nodes can also be interpreted as a topology. In this paper we propose a generic protocol, T-Man, intuitive and flexible manner. At the same time, the T-Man protocol involves only local communication
Etherlay: An Overlay Enhancement for Metro Ethernet Networks Minh Huynh and Prasant Mohapatraemail@example.com Abstract-- The ubiquitous Ethernet technology has propelled itself into a wide-scale adoption for Metro Ethernet Networks (MEN). Despite recent advancements in Ethernet and commercialization of the first
California at Davis, University of
PAVEMENT OVERLAY THICKNESS EVALUATION USING GROUND PENTRATING RADAR (GPR) Dwayne Harris, M.Sc., PG University, West Lafayette, IN 47907 firstname.lastname@example.org ABSTRACT Accurate knowledge of pavement thickness is important information to have both at a network and project level. This information aids in pavement
power consumption makes up a large part of global energy consumption. These home appliances are not only efficient power management. Index Terms--Home network, Energy saving, Green network- ing, Overlay control communication . Energy saving is recognized as a key issue in global warming and climate change. According
Eclipse Attacks on Overlay Networks: Threats and Defenses Atul Singh, Tsuen-Wan "Johnny" Ngan of peers, forming a graph upon which a distributed application or service is implemented. In an "Eclipse of malicious nodes can eclipse a large number of correct victim nodes. This paper studies the impact of Eclipse
Lo Cigno, Renato Antonio
Magnetic overlayers of Fe and Co have been investigated with X-ray Magnetic Circular Dichroism in X-ray Absorption Spectroscopy (XMCD-ABS) and Photoelectron Spectroscopy (PES), including Spin-Resolved Photoelectron Spectroscopy (SRPES), at Beamline 4 at the Advanced Photon Source (APS). Particular emphasis was placed upon the interrogation of the 2p levels of the Fe.
Tobin, J G; Yu, S; Butterfield, M T
As the Internet moves towards a three-layer architecture consisting of overlay networks on top of the IP network layer on top of WDM-based physical networks, incorporating the interaction between and among network layers is crucial for efficient and effective implementation of survivability. This dissertation has four major foci as follows:…
to request messages. Such a feature is of main concerns when designing censorship-resistant distributed of malicious peers to correlate overlay addresses to hosts for censorship or auditing purposes. 1. Introduction and message routing on top of the Internet addressing and packet routing scheme. Each host participating
The development of new maraging steel overlaying welding rod, which contains Co, Mo, W and V alloy, solved the problems of\\u000a poor homogeneity of hardness and mechanical process, prolonged the service life of wear-resistant components and increased\\u000a the productive efficiency of repairing, greatly benefiting the national economy.
Yong-ming Pan; Shao-wei Chen
Chapter 1433 HILLSIDE OVERLAY DISTRICTS Â§ 1433-01. Specific Purposes. Â§ 1433-03. Definitions regulations may precipitate landslides or excessive soil erosion. The additional regulations embodied-03. Definitions. For purposes of this chapter, words and phrases defined below have the meanings ascribed to them
As Moore's Law drives CD smaller and smaller, overlay budget is shrinking rapidly. Furthermore, the cost of advanced lithography tools prohibits usage of latest and greatest scanners on non-critical layers, resulting in different layers being exposed with different tools; a practice commonly known as 'mix and match.' Since each tool has its unique signature, mix and match becomes the source of high order overlay errors. Scanner alignment performance can be degraded by a factor of 2 in mix and match, compared to single tool overlay operation. In a production environment where scanners from different vendors are mixed, errors will be even more significant. Mix and match may also be applied to a single scanner when multiple illumination modes are used to expose critical levels. This is because different illuminations will have different impact to scanner aberration fingerprint. The semiconductor technology roadmap has reached a point where such errors are no longer negligible. Mix and match overlay errors consist of scanner stage grid component, scanner field distortion component, and process induced wafer distortion. Scanner components are somewhat systematic, so they can be characterized on non product wafers using a dedicated reticle. Since these components are known to drift over time it becomes necessary to monitor them periodically, per scanner, per illumination. In this paper, we outline a methodology for automating characterization of mix and match errors, and a control system for real-time correction.
Wakamoto, S.; Ishii, Y.; Yasukawa, K.; Sukegawa, A.; Maejima, S.; Kato, A.; Robinson, J. C.; Eichelberger, B. J.; Izikson, P.; Adel, M.
APPLICATION OF NELSON'S SORPTION ISOTHERM TO WOOD COMPOSITES AND OVERLAYS' Qinglin Wu Assistant. It was found that Nelson's model can be used to describe the experimental data from different composite composite materials (Suchsland 1972). These relationships, known as sorption isotherms, greatly affect
The LANDSAT 4 mission has unique characteristics relative to previous LANDSAT missions. The effects of these changes on the character of MSS radiometric data were explored. The histogram calibration process made a significant reduction of the channel differences within a band. If this improvement proves consistent over a wide radiometric range and persists over time, LANDSAT 4 MSS may not have the banding problems that plagued previous MSS instruments. For a simultaneous overpass of LANDSAT 3 and 4, uniform test areas were selected that were common in both data sets. Significant differences in radiance values between the two satellites were observed when R sub max and R sub min were used to compute obsolute radiance values. Ground truth should be used to determine new values. A woodgrain appearing pattern is apparent in the MSS images that were not apparent in previous MSS's. It is believed to be caused by many different frequency components, most of which originate from a common source.
Alford, W. L.; Imhoff, M. L.
Water specialists Rick Allen, Bill Kramber and Tony Morse use Landsat thermal band data to measure the amount of water evaporating from the soil and transpiring from plants? leaves ? a process call...
The measurement of registration errors in LANDSAT MSS data is discussed as well as the development of a revised algorithm for the radiometric calibration of TM data and the production of a geocoded TM image.
Strome, W. M.; Cihlar, J.; Goodenough, D. G.; Guertin, F. E. (principal investigators); Guindon, B.; Murphy, J.; Butlin, J. M.; Duff, P.; Fitzgerald, A.; Grieve, G.
The private sector was examined and evaluated to develop base line strategies and mechanisms for its increased utilization of LANDSAT (and future satellite) technologies as both consumer and producer of products and services. Methodologies used to assess the digital analysis service and national mapping industries are described. Private sector users in business and industry are identified and the potential U.S. industry role in the foreign LANDSAT market is considered.
The Landsat Thematic Mapper is a multispectral imaging sensor added to Landsats 4 and later. This site uses text, photographs, tables, and diagrams to explain how the Thematic Mapper works and the advantages of sensing radiation in wavelengths other than those normally visible to the human eye. It is part of NASA's Remote Sensing Tutorial and links to the rest of the tutorial are provided.
The design verification of the LANDSAT-D antenna subsystem is addressed. In particular, the analysis of the antenna radiation patterns utilizing a full scale mockup of the LANDSAT-D satellite is discussed. Test antennas included two S-Band shaped beam antennas, two S-Band omni unit radiators (to operate in array), a GPS antenna, an X-Band shaped beam antenna, and one S-Band high-gain parabolic antenna.
The interpretation of LANDSAT data for a regional geological investigation of Brazil is provided. Radar imagery, aerial photographs and aeromagnetic maps were also used. Automatic interpretation, using LANDSAT OCT's was carried out by the 1-100 equipment. As a primary result a tectonic map was obtained, at 1:1,000,000 scale, of an area of about 143,000 square kilometers, in the central portion of Minas Gerais and Eastern Goias States, known as regions potentially rich in mineral resources.
Dacunha, R. P.; Demattos, J. T.
Geological interpretation possibilities of SPOT MSS and LANDSAT MSS positive prints enlarged to the same scale were compared, using as a test area part of the Jebel Amour (Algeria). The SPOT imagery offers many advantages, filling the gap between remote sensing from space and aerial photography. The best results by visual interpretation are obtained in combining SPOT for the required details with LANDSAT for the synoptic veiw. Further improvements are expected from the use of SPOT stereo-pairs.
One of the major catalysts leading to the development of the global-scale Earth Systems Science concept, the International Geosphere-Biosphere Program, and the U.S. Global Change Research Program were the unique views of Earth provided by Landsat sensors over the past 25 years. This paper ad- dresses Landsat's contributions in the Earth Systems Science arena. Early successes in observing the Earth's
Samuel N. Goward; Darrel L. Williams
Vegetation Continuous Field (VCF) layers of 30 m percent tree cover, bare ground, other vegetation and probability of water were derived for the conterminous United States (CONUS) using Landsat 7 Enhanced Thematic Mapper Plus (ETM+) data sets from the Web-Enabled Landsat Data (WELD) project. Turnkey approaches to land cover characterization were enabled due to the systematic WELD Landsat processing, including conversion
Matthew C. Hansen; Alexey Egorov; David P. Roy; Peter Potapov; Junchang Ju; Svetlana Turubanova; Indrani Kommareddy; Thomas R. Loveland
Landsat satellites have provided unparalleled Earth-observing data for nearly 40 years, allowing scientists to describe, monitor and model the global environment during a period of time that has seen dramatic changes in population growth, land use, and climate. The success of the Landsat program can be attributed to well-designed instrument specifications, astute engineering, comprehensive global acquisition and calibration strategies, and innovative scientists who have developed analytical techniques and applications to address a wide range of needs at local to global scales (e.g., crop production, water resource management, human health and environmental quality, urbanization, deforestation and biodiversity). Early Landsat contributions included inventories of natural resources and land cover classification maps, which were initially prepared by a visual interpretation of Landsat imagery. Over time, advances in computer technology facilitated the development of sophisticated image processing algorithms and complex ecosystem modeling, enabling scientists to create accurate, reproducible, and more realistic simulations of biogeochemical processes (e.g., plant production and ecosystem dynamics). Today, the Landsat data archive is freely available for download through the USGS, creating new opportunities for scientists to generate global image datasets, develop new change detection algorithms, and provide products in support of operational programs such as Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (REDD). In particular, the use of dense (approximately annual) time series to characterize both rapid and progressive landscape change has yielded new insights into how the land environment is responding to anthropogenic and natural pressures. The launch of the Landsat Data Continuity Mission (LDCM) satellite in 2012 will continue to propel innovative Landsat science.
Cook, Bruce D.; Irons, James R.; Masek, Jeffrey G.; Loveland, Thomas R.
A Landsat MSS and TM classification approach based on three features derived from the greenness profile has proved very effective in separating and identifying corn, soybeans, and other ground cover classes in the U.S. The objective of this study is to investigate the separation of summer crops in Argentina, one of the most important commodity exporters, using the same greenness profile features that have proved effective in the U.S. Corn Belt. The area chosen for study is a more complex cropping practice area located in the north-west corner of Buenos Aires province in Pampa Humeda, where corn, soybean, sorghum, sunflower, and pastures are cultivated. It is shown that the profile features can provide very effective separation, except in the case of corn from sorghum. Separation between corn and soybeans was found to be greater than in the U.S. This study suggests that the automatic, unsupervised classification approach developed in the U.S., with relatively minor modification, can be used for summer crop area estimation in Argentina.
Badhwar, G. D.; Gargantini, C. E.; Redondo, F. V.
The Landsat Data Continuity Mission (LDCM) is scheduled for a December 2012 launch date. LDCM is being managed by an interagency partnership between NASA and the U.S. Geological Survey (USGS). In order to provide the necessary spectral coverage of the visible through shortwave-infrared (SWIR) and the thermal-infrared (TIR), the satellite will carry two sensors. The Operational Land Imager (OLI) will collect data for nine visible to shortwave spectral bands with a spatial resolution of 30 m (with a 15 m panchromatic band). The Thermal Infrared Sensor (TIRS) will collect coincident image data for two TIR bands with a spatial resolution of 100 m. The OLI is fully assembled and tested and has been shipped by it's manufacturer, Ball Aerospace and Technology Corporation, to the Orbital Sciences Corporation (Orbital) facility where it is being integrated onto the LDCM spacecraft. Pre-launch testing indicates that OLI will meet all performance specification with margin. TIRS is in development at the NASA Goddard Space F!ight Center (GSFC) and is in final testing before shipping to the Orbital facility in January, 2012. The presentation will describe the LDCM satellite instrument systems, present pre-launch performance data for OLI and TIRS, and present simulated images to highlight notable features and expected imaging performance.
Dabney, Philip W.; Irons, James R.; Markham, Brian L.; Reuter, Dennis C.; Storey, James C.
The Earth Observing System (EOS), the centerpiece of NASA's Earth science program, is a suite of spacecraft and interdisciplinary science investigations dedicated to advancing our understanding of global change. The flagship EOS satellite, Terra (formerly EOS AM-1), scheduled for launch in July 1999, will provide key measurements of the physical and radiative properties of clouds; air-land and air-sea exchanges of energy, carbon, and water; trace gases; and volcanoes. Flying in formation with Terra, Landsat 7 will make global high spatial resolution measurements of land surface and surrounding coastal regions. Other upcoming EOS missions and instruments include QuikSCAT, to collect sea surface wind data; the Stratospheric Gas and Aerosol Experiment (SAGE III), to create global profiles of key atmospheric gases; and the Active Cavity Radiometer Irradiance Monitors (ACRIM) to measure the energy output of the Sun. The second of the major, multi-instrument EOS platforms, PM-1, is scheduled for launch in 2000. Interdisciplinary research projects sponsored by EOS use specific Earth science data sets for a broader investigation into the function of Earth systems. Current EOS research spans a wide range of sciences, including atmospheric chemistry, hydrology, land use, and marine ecosystems. The EOS program has been managed since 1990 by the Goddard Space Flight Center in Greenbelt, Md., for NASA's Office of Earth Science in Washington, D. C. Additional information on the program can be found on the EOS Project Science Office Web site (http://eospso.gsfc.nasa.gov).
The year 2013 will be an exciting period for those that study the Earth land surface from space, particularly those that observe and characterize land cover, land use, and the change of cover and use over time. Two new satellite observatories will be launched next year that will enhance capabilities for observing the global land surface. The United States plans to launch the Landsat Data Continuity Mission (LDCM) in January. That event will be followed later in the year by the European Space Agency (ESA) launch of the first Sentinel 2 satellite. Considered together, the two satellites will increase the frequency of opportunities for viewing the land surface at a scale where human impact and influence can be differentiated from natural change. Data from the two satellites will provide images for similar spectral bands and for comparable spatial resolutions with rigorous attention to calibration that will facilitate cross comparisons. This presentation will provide an overview of the LDCM satellite system and report its readiness for the January launch.
Irons, James R.; Loveland, Thomas R.; Markham, Brian L.; Masek, Jeffrey G.; Cook, Bruce; Dwyer, John L.
Work done on evaluating the geometric and radiometric quality of early LANDSAT-4 sensor data is described. Band to band and channel to channel registration evaluations were carried out using a line correlator. Visual blink comparisons were run on an image display to observe band to band registration over 512 x 512 pixel blocks. The results indicate a .5 pixel line misregistration between the 1.55 to 1.75, 2.08 to 2.35 micrometer bands and the first four bands. Also a four 30M line and column misregistration of the thermal IR band was observed. Radiometric evaluation included mean and variance analysis of individual detectors and principal components analysis. Results indicate that detector bias for all bands is very close or within tolerance. Bright spots were observed in the thermal IR band on an 18 line by 128 pixel grid. No explanation for this was pursued. The general overall quality of the TM was judged to be very high.
Anuta, P. E. (principal investigator)
The Space Shuttle tile overlay repair concept, developed at the NASA Johnson Space Center, is designed for on-orbit installation over an area of damaged tile to permit safe re-entry. The thin flexible plate is placed over the damaged area and secured to tile at discreet points around its perimeter. A series of flutter analyses were performed to determine if the onset of flutter met the required safety margins. Normal vibration modes of the panel, obtained from a simplified structural analysis of the installed concept, were combined with a series of aerodynamic analyses of increasing levels of fidelity in terms of modeling the flow physics to determine the onset of flutter. Results from these analyses indicate that it is unlikely that the overlay installed at body point 1800 will flutter during re-entry.
Bey, Kim S.; Scott, Robert C.; Bartels, Robert E.; Waters, William A.; Chen, Roger
Epidemics seldom occur as isolated phenomena. Typically, two or more viral agents spread within the same host population and may interact dynamically with each other. We present a general model where two viral agents interact via an immunity mechanism as they propagate simultaneously on two networks connecting the same set of nodes. By exploiting a correspondence between the propagation dynamics and a dynamical process performing progressive network generation, we develop an analytical approach that accurately captures the dynamical interaction between epidemics on overlay networks. The formalism allows for overlay networks with arbitrary joint degree distribution and overlap. To illustrate the versatility of our approach, we consider a hypothetical delayed intervention scenario in which an immunizing agent is disseminated in a host population to hinder the propagation of an undesirable agent (e.g., the spread of preventive information in the context of an emerging infectious disease).
Marceau, Vincent; Noël, Pierre-André; Hébert-Dufresne, Laurent; Allard, Antoine; Dubé, Louis J.
Large scale scientific data transfers are central to scientific processes. Data from large experimental facilities have to be moved to local institutions for analysis or often data needs to be moved between local clusters and large supercomputing centers. In this paper, we propose and evaluate a network overlay architecture to enable highthroughput, on-demand, coordinated data transfers over wide-area networks. Our work leverages Phoebus and On-demand Secure Circuits and AdvanceReservation System (OSCARS) to provide high performance wide-area network connections. OSCARS enables dynamic provisioning of network paths with guaranteed bandwidth and Phoebus enables the coordination and effective utilization of the OSCARS network paths. Our evaluation shows that this approach leads to improved end-to-end data transfer throughput with minimal overheads. The achievedthroughput using our overlay was limited only by the ability of the end hosts to sink the data.
Ramakrishnan, Lavanya; Guok, Chin; Jackson, Keith; Kissel, Ezra; Swany, D. Martin; Agarwal, Deborah
Isolated and dense patterns were formed at process layers from gate through to back-end on wafers using a 90 nm logic device process utilizing ArF lithography under various lithography conditions. Pattern placement errors (PPE) between AIM grating and BiB marks were characterized for line widths varying from 1000nm to 140nm. As pattern size was reduced, overlay discrepancies became larger, a tendency which was confirmed by optical simulation with simple coma aberration. Furthermore, incorporating such small patterns into conventional marks resulted in significant degradation in metrology performance while performance on small pattern segmented grating marks was excellent. Finally, the data also show good correlation between the grating mark and specialized design rule feature SEM marks, with poorer correlation between conventional mark and SEM mark confirming that new grating mark significantly improves overlay metrology correlation with device patterns.
Ueno, Atsushi; Tsujita, Kouichirou; Kurita, Hiroyuki; Iwata, Yasuhisa; Ghinovker, Mark; Poplawski, Jorge M.; Kassel, Elyakim; Adel, Mike E.
The ability to detect and quantify changes in the Earth's environment depends on satellites sensors that can provide calibrated, consistent measurements of Earth's surface features through time. A critical step in this process is to put image data from subsequent generations of sensors onto a common radiometric scale. To evaluate Landsat-5 (L5) Thematic Mapper's (TM) utility in this role, image pairs from the L5 TM and Landsat-7 (L7) Enhanced Thematic Mapper Plus (ETM+) sensors were compared. This approach involves comparison of surface observations based on image statistics from large common areas observed eight days apart by the two sensors. The results indicate a significant improvement in the consistency of L5 TM data with respect to L7 ETM+ data, achieved using a revised Look-Up-Table (LUT) procedure as opposed to the historical Internal Calibrator (IC) procedure previously used in the L5 TM product generation system. The average percent difference in reflectance estimates obtained from the L5 TM agree with those from the L7 ETM+ in the Visible and Near Infrared (VNIR) bands to within four percent and in the Short Wave Infrared (SWIR) bands to within six percent.
Chander, G.; Markham, B.L.; Micijevic, E.; Teillet, P.M.; Helder, D.L.
In order to degrade the self participants in the peer-to-peer overlay networks, a rerouting-based anonymous communication strategy respect with reputation mechanism, which does not need an administrating node, is put forward in this paper. The degree of anonymity of the inactive participant is degraded by the value of reputation, and the active participants achieve better degree of anonymity in the
Yanhui Wu; Sichun Wang
A number of large-scale distributed Internet applications could potentially benefit from some level of knowledge about the relative proximity between its participating host nodes. For example, the perfor- mance of large overlay networks could be improved if the application-level connectivity between the nodes in these networks is congruent with the un- derlying IP-level topology. Similarly, in the case of replicated
Sylvia Ratnasamy; Mark Handley; Richard M. Karp; Scott Shenker
Peer-to-Peer (P2P) computing systems are rapidly growing in importance as the medium of choice for the mass storage. Peers in the most P2P systems randomly choose logical neighbors without any knowledge about underlying physical topology. This mechanism can cause a serious topology mismatch between the P2P overlay network and the underlying network. It greatly limits the performance gain from various
Xiaoming Zhang; Zhoujun Li; Yijie Wang
Rice is one of the most important cereal crops in the world and is the major crop in Taiwan. However, it is a challenge because rice fields are generally small and fragmental, while crop mapping requires information of crop phenology associating with the high spatiotemporal resolution of remote-sensing data. This problem can be partially overcome by a spatiotemporal fusion to create a new dataset that has a better spatiotemporal resolution. In this study, the Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat imageries were used because MODIS data, which a spatial resolution of land bands of 500 m and temporal resolution of 1-2 days, were able to achieve the phenological information of rice crops at a large region; while Landsat data demonstrate the effectiveness to collectively map small patches of crop fields at the subnational level due to its spatial resolution of 30 m. However, the temporal resolution of Landsat data is lower (16 days), making it difficult to investigate temporal responses of crop phenology from rice fields. The main objective of this study was to take into account of advantages of MODIS and Landsat imageries to generate a synthetic dataset at Landsat spatial resolution and MODIS temporal resolution for rice crop mapping in Taiwan. The methodology comprised five steps: (1) satellite data for 2011 were pre-processed to account for geometric and radiometric correction of MODIS and Landsat data, (2) MODIS-Landsat data fusion using the Spatial Temporal Adaptive Fusion Model (STARFM), (3) construct the smooth time-series Normalized Difference Vegetation Index (NDVI) data using wavelet transform, (4) rice crop classification using phenological information of crop phenology, and (5) accuracy assessment. The data fusion results for day of year (DOY) 153 were compared with the reference Landsat data (DOY 153) indicated a close correlation (R2 = 0.81). The phenology-based classification results compared with the ground reference data revealed close agreement between these two datasets. The overall accuracy and Kappa coefficient were 82% and 0.75, respectively. The relationship between the MODIS-derived rice areas and those from the government's rice area statistics at the district level was examined, reaffirming a strong correlation between the two datasets with R2 > 0.9. This study demonstrates advantages of MODIS-Landsat data fusion for rice crop mapping in Taiwan. Such an approach used in this study could be applied for other regions to map small patches of crops at a subnational scale.
Chen, Cheng-Ru; Chen, Chi-Farn; Son, Nguyen-Thanh
As the overlay performance and accuracy requirements become tighter, the impact of process parameters on the target signal becomes more significant. Traditionally, in order to choose the optimum overlay target, several candidates are placed in the kerf area. The candidate targets are tested under different process conditions, before the target to be used in mass production is selected. The varieties of targets are left on the mass production mask and although they will not be used for overlay measurements they still consume kerf real estate. To improve the efficiency of the process we are proposing the KTD (KLA-Tencor Target Designer). It is an easy to use system that enables the user to select the optimum target based on advanced signal simulation. Implementing the KTD in production is expected to save 30% of kerf real estate due to more efficient target design process as well as reduced engineering time. In this work we demonstrate the capability of the KTD to simulate the Archer signal in the context of advanced DRAM processes. For several stacks we are comparing simulated target signals with the Archer100 signals. We demonstrate the robustness feature in the KTD application that enables the user to test the target sensitivity to process changes. The results indicate the benefit of using KTD in the target optimization process.
Marchelli, Anat; Gutjahr, Karsten; Kubis, Michael; Sparka, Christian; Ghinovker, Mark; Navarra, Alessandra; Widmann, Amir
Currently, most blades and vanes in the hottest section of aero gas turbine engines require some type of coating for oxidation protection. Newly developed single crystal superalloys have the mechanical potential to operate at increasingly higher component temperatures. However, at these elevated temperatures, coating/substrate interdiffusion can shorten the protective life of the coating. Diffusion barriers between overlay coatings and substrates are being examined to extend the protective life of the coating. A previously- developed finite-difference diffusion model has been modified to predict the oxidative life enhancement due to use of a diffusion barrier. The original diffusion model, designated COSIM, simulates Al diffusion in the coating to the growing oxide scale as well as Al diffusion into the substrate. The COSIM model incorporates an oxide growth and spalling model to provide the rate of Al consumption during cyclic oxidation. Coating failure is predicted when the Al concentration at the coating surface drops to a defined critical level. The modified COSIM model predicts the oxidative life of an overlay coating when a diffusion barrier is present eliminating diffusion of Al from the coating into the substrate. Both the original and the modified diffusion models have been used to predict the effectiveness of a diffusion barrier in extending the protective life of a NiCrAl overlay coating undergoing cyclic oxidation at 1100 C.
Nesbitt, James A.; Lei, Jih-Fen
Key-based routing has enabled efficient group communication on the application or service middleware layer, stimulated by the need of applications to access multicast. These developments follow a continuous debate about network layer multicast that had lasted for about 30 years history of the Internet. The IP host group model today still faces a strongly divergent state of deployment. In this chapter, we first review the key concepts of multicast and broadcast data distribution on structured overlays. Second, we perform a comprehensive theoretical analysis examining the different distribution trees constructed on top of a key-based routing layer. Characteristic performance measures of the multicast approaches are compared in detail and major structural differences are identified. Overlay multicast overcomes deployment problems on the price of a performance penalty. Hybrid approaches, which dynamically combine multicast in overlay and underlay, adaptively optimize group communication. We discuss current schemes along with its integration in common multicast routing protocols in the third part of this chapter. Finally, we reconsider and enhance approaches to a common API for group communication, which serves the requirements of data distribution and maintenance for multicast and broadcast on a middleware abstraction layer, and in particular facilitates hybrid multicast schemes.
Wählisch, Matthias; Schmidt, Thomas C.
Objective and unbiased validation studies over a significant number of cases are required to get a more solid picture on craniofacial superimposition reliability. It will not be possible to compare the performance of existing and upcoming methods for craniofacial superimposition without a common forensic database available for the research community. Skull-face overlay is a key task within craniofacial superimposition that has a direct influence on the subsequent task devoted to evaluate the skull-face relationships. In this work, we present the procedure to create for the first time such a dataset. We have also created a database with 19 skull-face overlay cases for which we are trying to overcome legal issues that allow us to make it public. The quantitative analysis made in the segmentation and registration stages, together with the visual assessment of the 19 face-to-face overlays, allows us to conclude that the results can be considered as a gold standard. With such a ground truth dataset, a new horizon is opened for the development of new automatic methods whose performance could be now objectively measured and compared against previous and future proposals. Additionally, other uses are expected to be explored to better understand the visual evaluation process of craniofacial relationships in craniofacial identification. It could be very useful also as a starting point for further studies on the prediction of the resulting facial morphology after corrective or reconstructive interventionism in maxillofacial surgery. PMID:25267257
Ibáñez, O; Cavalli, F; Campomanes-Álvarez, B R; Campomanes-Álvarez, C; Valsecchi, A; Huete, M I
The Landsat Technical Working Group (LTWG) and the Landsat Ground Station Operations Working Group (LGSOWG) have encouraged Landsat receiving stations around the world to share information about their data holdings through the exchange of metadata records. Receiving stations forward their metadata records to the U.S. Geological Survey's EROS Data Center (EDC) on a quarterly basis. The EDC maintains the records for each station, coordinates changes to the database, and provides metadata to the stations as requested. The result is a comprehensive international database listing most of the world's Landsat data acquisitions This exchange of information began in the early 1980's with the inclusion in the EDC database os scenes acquired by a receiving station in Italy. Through the years other stations have agreed to participate; currently ten of the seventeen stations actively share their metadata records. Coverage maps have been generated to depict the status of the database. The Worldwide Landsat database is also available though the Global Land Information System (GLIS).
Smith, Timothy B.; Goodale, Katherine L.
Results of a sedimentary rock type discrimination project using Seasat radar and Landsat multispectral image data of the San Rafael Swell, in eastern Utah, are presented, which has the goal of determining the potential contribution of radar image data to Landsat image data for rock type discrimination, particularly when the images are coregistered. The procedure employs several images processing techniques using the Landsat and Seasat data independently, and then both data sets are coregistered. The images are evaluated according to the ease with which contacts can be located and rock units (not just stratigraphically adjacent ones) separated. Results show that of the Landsat images evaluated, the image using a supervised classification scheme is the best for sedimentary rock type discrimination. Of less value, in decreasing order, are color ratio composites, principal components, and the standard color composite. In addition, for rock type discrimination, the black and white Seasat image is less useful than any of the Landsat color images by itself. However, it is found that the incorporation of the surface textural measures made from the Seasat image provides a considerable and worthwhile improvement in rock type discrimination.
Blom, R.; Abrams, M.; Conrad, C.
The National Aeronautics and Space Administration (NASA) plans to procure data from a privately-owned and commercially-operated remote sensing system for the next Landsat mission, the Landsat Data Continuity Mission (LDCM). Data requirements are documented in an LDCM Data Specification. The specifications require delivery of data covering 250 Landsat scenes on a daily basis. The data are to be acquired in a manner that affords seasonal coverage of the global land mass. Data are required for the heritage reflective Thematic Mapper (TM) spectral bands plus two new bands, a blue band for coastal zone observations and a short wave infrared band for cirrus cloud detection. The specifications do not require thermal data, representing a departure from the TM heritage. The specification also requires data providing a 30 m ground sample distance for each of the spectral bands with the exception of the new cirrus cloud band at 120 m. An absolute uncertainty of 5 percent or less is required for radiometrically corrected LDCM data and the commercial operator is required to deliver data that can be registered to a cartographic projection with an uncertainty of 65 m or less. Procuring data from a commercial operator represents a new approach for the 30-year-old Landsat Program. The LDCM Data Specification will ensure that the procured data provides continuity of the Landsat data stream and advances the mission.
Irons, J.R.; Speciale, N.J.; Douglas, McCuistion J.; Masek, J.G.; Markham, B.L.; Storey, J.C.; Lencioni, D.E.; Ryan, R.E.
In one of the greatest ecological disasters of our time, the ancient marshlands of Mesopotamia are systematically being converted to dry salt flats as a result of human mismanagement of the regions water resources.Landsat satellite imagery reveals that in the last 10 years, wetlands that once covered as much as 20,000 square km in parts of Iraq and Iran have been reduced to a small fraction of their original size. The authors of a new report released by the United Nations Environment Programmes (UNEP) at the 11th Stockholm Water Symposium on August 13, 2001, warn that the marshlands could completely disappear within the next 3-5 years unless dramatic steps are taken immediately to reverse the damage being done. The UNEP Executive Director described the wetlands condition as a major environmental catastrophe that will be remembered as one of humanitys worst engineered disasters. He noted that the tragic loss of this rare wetland has occurred in approximately the same period since world leaders pledged to safeguard the environment at the United Nations Conference on Environment and Development (the Earth Summit) held in Rio de Janeiro in 1992. Regarded by historians as one of the cradles of civilization, the Mesopotamian Fertile Crescent has supported Marsh Arab society for millennia. But through the damming and siphoning off of waters from the Tigris and Euphrates Rivers, the countries of Iran, Iraq, Turkey, and Syria have decimated the ecosystem and, with it, a culture rooted in the dawn of human history (dating back to ancient Sumeria about 5,000 years ago).
As overlay margins shrink for advanced process nodes, a key overlay metrology challenge is finding the measurement conditions which optimize the yield for every device and layer. Ideally, this setup should be found in-line during the lithography measurements step. Moreover, the overlay measurement must have excellent correlation to the device electrical behavior. This requirement makes the measurement conditions selection even more challenging since it requires information about the response of both the metrology target and device to different process variations. In this work a comprehensive solution for overlay metrology accuracy, used by UMC, is described. This solution ranks the different measurement setups by their accuracy, using Qmerit, as reported by the Archer 500. This ranking was verified to match device overlay using electrical tests. Moreover, the use of Archer Self Calibration (ASC) allows further improvement of overlay measurement accuracy.
Hsu, Simon C. C.; Chen, Charlie; Yu, Chun Chi; Pai, Yuan Chi; Amit, Eran; Yap, Lipkong; Itzkovich, Tal; Tien, David; Huang, Eros; Kuo, Kelly T. L.; Amir, Nuriel
The author has identified the following significant results. Some 50 LANDSAT images displaying mesoscale cloud features were analyzed. This analysis was based on the Rayleigh-Kuettner model describing the formation of that type of mesoscale cloud feature. This model lends itself to computation of the average wind speed in northerly flow from the dimensions of the cloud band configurations measured from a LANDSAT image. In nearly every case, necessary conditions of a curved wind profile and orientation of the cloud streets within 20 degrees of the direction of the mean wind in the convective layer were met. Verification of the results by direct observation was hampered, however, by the incompatibility of the resolution of conventional rawinsonde observations with the scale of the banded cloud patterns measured from LANDSAT data. Comparison seems to be somewhat better in northerly flows than in southerly flows, with the largest discrepancies in wind speed being within 8m/sec, or a factor of two.
Sherr, P. E. (principal investigator); Feteris, P. J.; Lisa, A. S.; Bowley, C. J.; Fowler, M. G.; Barnes, J. C.
LANDSAT radiance data were used in an experiment conducted on the waters of Kerr Reservoir to determine if reliable algorithms could be developed that relate water quality parameters to remotely sensed data. A mix of different types of algorithms using the LANDSAT bands was generated to provide a thorough understanding of the relationships among the data involved. Except for secchi depth, the study demonstrated that for the ranges measured, the algorithms that satisfactorily represented the data encompass a mix of linear and nonlinear forms using only one LANDSAT band. Ratioing techniques did not improve the results since the initial design of the experiment minimized the errors against which this procedure is effective. Good correlations were found for total suspended solids, iron, turbidity, and secchi depth. Marginal correlations were discovered for nitrate and tannin + lignin. Quantification maps of Kerr Reservoir are presented for many of the water quality parameters using the developed algorithms.
Lecroy, S. R. (principal investigator)
Landsat-4 was launched on July 16, 1982, while the launch of Landsat-5 took place on March 1, 1984. The earth-observing instruments employed were the Multispectral Scanner (MSS), which has flown since 1972 on Landsat satellites, and the Thematic Mapper (TM). The TM provides improved spatial radiance and spectral resolution. The improved capabilities of the TM, the use of different scanning mechanisms relative to the MSS, and the use of a new spacecraft with different mechanical operating characteristics led to a significant challenge in processing the TM and MSS data. The current paper has mainly the objective to present recent results which can provide information regarding the quality of processing as measured against specifications. The results obtained so far for the Thematic Mapper Image Processing System (TIPS), though limited, are found to be quite encouraging as far as the geometric processing of the TM is concerned.
Beyer, E. P.; Brooks, J.; Salomonson, V. V.
Community workshops, field visits, telephone surveys, and other research reveals that professionals at the substate level are interested in and open to consideration of LANDSAT as a planning and resource management tool, but are at the same time skeptical about some of the inherent problems with LANDSAT such as cost, resolution, frequency of coverage, and data continuity. The principal requirements for increasing the utilization of LANDSAT by potential substate users were identified and documented. Without a committment from the Federal Government for increased substrate utilization and the availability of trained professionals to meet the needs of a largely new user community, substrate activity is likely to remain at a minimum. Well conceived and well executed demonstration projects could play a critical role is shaping the technology's ability to be more sensitive to substate user needs and interests as well as validating the effectiveness of this data to a skeptical audience.
Landsat multispectral scanner data was applied to an urban change detection problem in Denver, CO. A dichotomous key yielding ten stages of residential development at the urban fringe was developed. This heuristic model allowed one to identify certain stages of development which are difficult to detect when performing digital change detection using Landsat data. The stages of development were evaluated in terms of their spectral and derived textural characteristics. Landsat band 5 (0.6-0.7 micron) and texture data produced change detection maps which were approximately 81 percent accurate. Results indicated that the stage of development and the spectral/textural features affect the change in the spectral values used for change detection. These preliminary findings will hopefully prove valuable for improved change detection at the urban fringe.
Jensen, J. R.; Toll, D. L.
Some 512 by 512 pixel subwindows for simultaneously acquired scene pairs obtained by LANDSAT 2,3 and 4 multispectral band scanners were coregistered using LANDSAT 4 scenes as the base to which the other images were registered. Scattergrams between the coregistered scenes (a form of contingency analysis) were used to radiometrically compare data from the various sensors. Mode values were derived and used to visually fit a linear regression. Root mean square errors of the registration varied between .1 and 1.5 pixels. There appear to be no major problem preventing the use of LANDSAT 4 MSS with previous MSS sensors for change detection, provided the noise interference can be removed or minimized. Data normalizations for change detection should be based on the data rather than solely on calibration information. This allows simultaneous normalization of the atmosphere as well as the radiometry.
Likens, W. C.; Wrigley, R. C.
A LANDSAT scene simulation capability was developed to study the effects of small fields and misregistration on LANDSAT-based crop proportion estimation procedures. The simulation employs a pattern of ground polygons each with a crop ID, planting date, and scale factor. Historical greenness/brightness crop development profiles generate the mean signal values for each polygon. Historical within-field covariances add texture to pixels in each polygon. The planting dates and scale factors create between-field/within-crop variation. Between field and crop variation is achieved by the above and crop profile differences. The LANDSAT point spread function is used to add correlation between nearby pixels. The next effect of the point spread function is to blur the image. Mixed pixels and misregistration are also simulated.
Pont, W. F., Jr. (principal investigator)
A Landsat scene simulation capability was developed to study the effects of small fields and misregistration on Landsat-based crop proportion estimation procedures. The simulation employs a pattern of ground polygons each with a crop ID, planting date, and scale factor. Historical greenness/brightness crop development profiles generate the mean signal values for each polygon. Historical within-field covariances add texture to pixels in each polygon. The planting dates and scale factors create between-field/within-crop variation. Between field and crop variation is achieved by the above and crop profile differences. The Landsat point spread function is used to add correlation between nearby pixels. The next effect of the point spread function is to blur the image. Mixed pixels and misregistration are also simulated. Previously announced in STAR as N82-32813
Pont, W. F., Jr.
Landsat TM and ETM+ imagery was used to distinguish areas of high vs. low cover of Amur honeysuckle (Lonicera maackii), taking advantage of the late leaf retention of this invasive shrub. L. maackii cover was measured in eight stands and compared to 15 Landsat 5 TM and Landsat 7 ETM+ images from spring and autumn dates from 1999 to 2006.
J. Resasco; A. N. Hale; M. C. Henry; D. L. Gorchov
In this paper were used Landsat TM images and supervised classification in order to distinguish crop areas and obtained the crop classification for the Nilo Coelho scheme. For land -use classification band 4, 5, 3 (Landsat TM) was assigned to Red Green Blue (RGB). A commercial software package (ERDAS Imagine v. 8.5) was available for the processing of the Landsat
EDWIN NOORDMAN; MAGNA SOELMA BEZERRA DE MOURA; MARCONI ANTÃO DOS SANTOS; MARIA DAS GRAÇAS; LOPES DOS SANTOS; HELIO LEANDRO LOPES
The compilation of global Landsat data-sets and the ever-lowering costs of computing now make it feasible to monitor the Earth’s land cover at Landsat resolutions of 30 m. In this article, we describe the methods to create global products of forest cover and cover change at Landsat resolutions. Neve...
The author has identified the following significant results. This research did not show the total potential of the LANDSAT system, but tried to open up new research aspects for the utilization of LANDSAT data in natural resource control. Results obtained through this research showed that LANDSAT data can be used to develop monitoring programs in the tropical forest areas of Brazil.
Dejesusparada, N. (principal investigator); Dossantos, A. P.; Demoraisnovo, E. M. L.
Multispectral remote sensing of the Earth using Landsat sensors was ushered on July 23, 1972, with the launch of Landsat-1. Following that success, four more Landsat satellites were launched, and each of these carried the Multispectral Scanner System (MSS). These five sensors provided the only consistent multispectral space-based imagery of the Earth's surface from 1972 to 1982. This work focuses on developing both a consistent and absolute radiometric calibration of this sensor system. Cross-calibration of the MSS was performed through the use of pseudoinvariant calibration sites (PICSs). Since these sites have been shown to be stable for long periods of time, changes in MSS observations of these sites were attributed to changes in the sensors themselves. In addition, simultaneous data collections were available for some MSS sensor pairs, and these were also used for cross-calibration. Results indicated substantial differences existed between instruments, up to 16%, and these were reduced to 5% or less across all MSS sensors and bands. Lastly, this paper takes the calibration through the final step and places the MSS sensors on an absolute radiometric scale. The methodology used to achieve this was based on simultaneous data collections by the Landsat-5 MSS and Thematic Mapper (TM) instruments. Through analysis of image data from a PICS location and through compensating for the spectral differences between the two instruments, the Landsat-5 MSS sensor was placed on an absolute radiometric scale based on the Landsat-5 TM sensor. Uncertainties associated with this calibration are considered to be less than 5%.
Helder, Dennis L.; Karki, Sadhana; Bhatt, Rajendra; Micijevik, Esad; Aaron, David; Jasinski, Benjamin
An analysis of LANDSAT Thematic Mapper (TM) data of the Pasterze Glacier and the Kleines Fleisskees in the Austrian Alps was undertaken and compared with meteorological data of nearby weather stations. Alpine or valley glaciers can be used to study regional and worldwide climate changes. Alpine glaciers respond relatively fast to a warming or cooling trend in temperature through an advance or a retreat of the terminus. In addition, the mass balance of the glacier is being affected. Last year two TM scenes of the Pasterze Glacier of Aug. 1984 and Aug. 1986 were used to study the difference in reflectance. This year, in addition to the scenes from last year, one MSS scene of Aug. 1976 and a TM scene from 1988 were examined for both the Pasterze Glacier and the Kleines Fleisskees. During the overpass of the LANDSAT on 6 Aug. 1988 ground truthing on the Pasterze Glacier was undertaken. The results indicate that there was considerable more reflectance in 1976 and 1984 than in 1986 and 1988. The climatological data of the weather stations Sonnblick and Rudolfshuette were examined and compared with the results found through the LANDSAT data. There were relations between the meteorological and LANDSAT data: the average temperature over the last 100 years showed an increase of .4 C, the snowfall was declining during the same time period but the overall precipitation did not reveal any significant change over the same period. With the use of an interactive image analysis computer, the LANDSAT scenes were studied. The terminus of the Pasterze Glacier retreated 348 m and the terminus of the Kleines Fleisskees 121 m since 1965. This approach using LANDSAT MSS and TM digital data in conjunction with meteorological data can be effectively used to monitor regional and worldwide climate changes.
Bayr, Klaus J.
In this paper, the authors present theoretical evidence for ferromagnetism in Ru and Rh overlayers on Ag(001). These predictions are based on ab-initio, spin-polarized, electronic-structure calculations within the framework of the local spin-density approximation. For Tc, Ru, Rh, and Pd overlayers chemisorbed on Ag(001), only Ru and Rh exhibited ferromagnetism. Several metamagnetic spin states were found for the Ru overlayers.
Eriksson, O.; Albers, R.C.; Boring, A.M. (Los Alamos National Lab., NM (United States). Theoretical Div.); Fernando, G.W. (Connecticut Univ., Storrs, CT (United States). Dept. of Physics); Cooper, B.R. (West Virginia Univ., Morgantown, WV (United States). Dept. of Physics)
The geodetic accuracy of LANDSAT 4 data from both the MSS and TM processing systems was evaluated. The procedure was based on comparing the calculated image location, computed with the geodetic referencing algorithms, with the true image location visually located on a display device. Results of the testing of geodetic accuracy of three MSS scenes (Washington, DC, central Alabama, and Los Angeles, CA) and two TM scenes (Aberdeen, SD and Galesburg, IL) are presented. The calculated and actual image locations of the ground control points are shown. The offset between the calculated and actual image location, as well as the offset vector magnitude or pixel error, are given.
Thormodsgard, J. M.; Devries, D. J.
Landsat data availability provides opportunity for improving the knowledge of the Siberian ecosystems necessary for quantifying the response of the regional carbon cycle to the climate change. We developed a new wetland map based on Landsat data for whole West Siberia aiming at scaling up the methane emission observations. Mid-summer Landsat scenes were used in supervised classification method, based on ground truth data obtained during multiple field surveys. The method allows distinguishing following wetland types: pine-dwarf shrubs-sphagnum bogs or ryams, ridge-hollows complexes, shallow-water complexes, sedge-sphagnum poor fens, herbaceous-sphagnum poor fens, sedge-(moss) poor fens and fens, wooded swamps or sogra, palsa complexes. In our estimates wetlands cover 36% of the taiga area. Total methane emission from WS taiga mires is estimated as 3.6 TgC/yr,which is 77% larger as compared to the earlier estimate based on partial Landsat mapping combined with low resolution map due to higher fraction of fen area. We make an attempt to develop a forest typology system useful for a dynamic vegetation modeling and apply it to the analysis of the forest type distribution for several test areas in West and East Siberia, aiming at capability of mapping whole Siberian forests based on Landsat data. Test region locations are: two in West Siberian middle taiga (Laryegan and Nyagan), and one in East Siberia near Yakutsk. The ground truth data are based on analysis of the field survey, forest inventory data from the point of view of the successional forest type classification. Supervised classification was applied to the areas where ample ground truth and inventory data are available, using several limited area maps and vegetation survey. In Laryegan basin the upland forest areas are dominated (as climax forest species) by Scots pine on sandy soils and Siberian pine with presence of fir and spruce on the others. Those types are separable using Landsat spectral data alone. In the permafrost area around Yakutsk the most widespread succession type is birch to larch succession. Three stages of the birch to larch succession are detectable from Landsat image. When Landsat data is used in both West and East Siberia, distinction between deciduous broad-leaved species (birch, aspen, and willow) is difficult due to similarity in spectral signatures. Same problem exists for distinguishing between dark coniferous species (Siberian pine, fir and spruce). Forest classification can be improved by applying landscape type analysis, such as separation into floodplain, terrace, sloping hills.
Maksyutov, Shamil; Kleptsova, Irina; Glagolev, Mikhail; Sedykh, Vladimir; Kuzmenko, Ekaterina; Silaev, Anton; Frolov, Alexander; Nikolaeva, Svetlana; Fedorov, Alexander
Radiometric characteristics have been examined of the Landsat-4 and Landsat-5 Thematic Mappers (TMs) that can be established without absolute calibration of spectral data. This analysis is based on radiometrically and geometrically raw (B-type) data of both uniform (flat-field) and high-contrast scenes. Subscenes selected for uniform radiance were used to characterized subtle radiometric differences and noise problems. Although the general performance of the Thematic Mappers is excellent, various anomalies that have a magnitude of a few digital levels (DN) or less are quantified. -from Authors
Kieffer, H.H.; Cook, D.A.; Eliason, E.M.; Eliason, P.T.
The formats used for the transmission of LANDSAT-D and LANDSAT-D Prime spacecraft telemetry data through either the TDRS/GSTDN via the NASCOM Network to the CSF are described as well as the telemetry flow from the command and data handling subsystem, a telemetry list and telemetry matrix assignment for the mission and engineering formats. The on-board computer (OBC) controlled format and the dwell format are also discussed. The OBCs contribution to telemetry, and the format of the reports, are covered. The high rate data channel includes the payload correction data format, the narrowband tape recorder and the OBC dump formats.
A legend is suggested for use with computer-generated thematic maps made from Landsat digital data that designates some of the radiometric characteristics of each thematic map unit as well as the described terrain attributes of each map unit. The relationship between spectral band and radiance for each map unit is shown by a two-dimensional polygon with the four Landsat multispectral scanner bands plotted on the ordinate and radiance levels on the abscissa. The resulting shape is colored to correspond with the map unit color, thus facilitating the recognition and understanding of the computer-generated map units.
Robinove, Charles J.
Comparison between Landsat-1 and -2 imagery of Arkansas provided evidence of significant land use changes during the 1972-75 time period. Analysis of Arkansas historical water quality information has shown conclusively that whereas point source pollution generally can be detected by use of water quality data collected by state and federal agencies, sampling methodologies for nonpoint source contamination attributable to surface runoff are totally inadequate. The expensive undertaking of monitoring all nonpoint sources for numerous watersheds can be lessened by implementing Landsat change detection analyses.
Macdonald, H. C.; Steele, K. F.; Waite, W. P.; Shinn, M. R.
Raw digital data, as received from the LANDSAT spacecraft, cannot generate images that meet specifications. Radiometric corrections must be made to compensate for aging and for differences in sensitivity among the instrument sensors. Geometric corrections must be made to compensate for off-nadir look angle, and to calculate spacecraft drift from its prescribed path. Corrections must also be made for look-angle jitter caused by vibrations induced by spacecraft equipment. The major components of the LANDSAT ground segment and their functions are discussed.
The history of the development and utilization of LANDSAT satellites is summarized. Objectives of the LANDSAT D mission are listed and the capabilities of the 4-channel multispectral band scanner and the 7-channel radiometer (thematic mapper) to be carried on the satellite are described. Satellite components are illustrated and diagrams show the ground segment data management system, the data assessment system, and the operations control center. The flight segment of the mission and flight segment specifications are also described. Examples of digitally analyzed and enhanced imagery are included.
One of the main challenges for 3D interconnect metrology of bonded wafers is measuring through opaque silicon wafers using conventional optical microscopy. We demonstrate here the use infrared microscopy, enhanced by implementing the differential interference contrast (DIC) technique, to measure the wafer bonding overlay. A pair of two dimensional symmetric overlay marks were processed at both the front and back sides of thinned wafers to evaluate the bonding overlay. A self-developed analysis algorithm and theoretical fitting model was used to map the overlay error between the bonded wafers and the interconnect structures. The measurement accuracy was found to be better than 1.0 micron. PMID:23938801
Ku, Yi-sha; Shyu, Deh-Ming; Lin, Yeou-Sung; Cho, Chia-Hung
Landsat Thematic Mapper (TM) and aircraft-borne Thematic Mapper simulator (TMS) data were collected over two areas of natural vegetation in southern California exposed to gradients of pollutant dose, particularly in photochemical oxidants: the coastal sage scrub of the Santa Monica Mountains in the Los Angeles basin, and the yellow pine forests in the southern Sierra Nevada. In both situations, natural variations in canopy closure, with subsequent exposure of understory elements (e.g.,rock or soil, chaparral, grasses, and herbs), were sufficient to cause changes in spectral variation that could obscure differences due to visible foliar injury symptoms observed in the field. TM or TMS data are therefore more likely to be successful in distinguishing pollution injury from background variation when homogeneous communities with closed canopies are subjected to more severe pollution-induced structural and/or compositional change. The present study helps to define the threshold level of vegetative injury detectable by TM data.
Westman, Walter E.; Price, Curtis V.
Flexible electronic devices call for copper and gold metal films to adhere well to polymer substrates. Measuring the interfacial adhesion of these material systems is often challenging, requiring the formulation of different techniques and models. Presented here is a strategy to induce well defined areas of delamination to measure the adhesion of copper films on polyimide substrates. The technique utilizes a stressed overlayer and tensile straining to cause buckle formation. The described method allows one to examine the effects of thin adhesion layers used to improve the adhesion of flexible systems. PMID:25641995
Cordill, M.J.; Marx, V.M.; Kirchlechner, C.
01/giu/2006 15/ott/2013LocalitÃ Paese/zona Overlay mappa Riepilogo Acquisizione Comportamento,43% 43 51,43% 3,46 00:01:41 0,00% 0 US$ 0,00 7. Switzerland 57 77,19% 44 43,86% 4,95 00:02:19 0,00% 0 US,00 27. Dominican Republic 4 100,00% 4 75,00% 4,00 00:02:51 0,00% 0 US$ 0,00 28. Japan 4 50,00% 2 50
Process-induced overlay errors are a growing problem in meeting the ever-tightening overlay requirements for integrated circuit production. Although uniform process-induced stress is easily corrected, nonuniform stress across the wafer is much more problematic, often resulting in noncorrectable overlay errors. Measurements of the wafer geometry of free, unchucked wafers give a powerful method for characterization of such nonuniform stress-induced wafer distortions. Wafer geometry data can be related to in-plane distortion of the wafer pulled flat by an exposure tool vacuum chuck, which in turn relates to overlay error. This paper will explore the relationship between wafer geometry and overlay error by the use of silicon test wafers with deliberate stress variations, i.e., engineered stress monitor (ESM) wafers. A process will be described that allows the creation of ESM wafers with nonuniform stress and includes many thousands of overlay targets for a detailed characterization of each wafer. Because the spatial character of the stress variation is easily changed, ESM wafers constitute a versatile platform for exploring nonuniform stress. We have fabricated ESM wafers of several different types, e.g., wafers where the center area has much higher stress than the outside area. Wafer geometry is measured with an optical metrology tool. After fabrication of the ESM wafers including alignment marks and first level overlay targets etched into the wafer, we expose a second level resist pattern designed to overlay with the etched targets. After resist patterning, relative overlay error is measured using standard optical methods. An innovative metric from the wafer geometry measurements is able to predict the process-induced overlay error. We conclude that appropriate wafer geometry measurements of in-process wafers have strong potential to characterize and reduce process-induced overlay errors.
Brunner, Timothy A.; Menon, Vinayan C.; Wong, Cheuk Wun; Gluschenkov, Oleg; Belyansky, Michael P.; Felix, Nelson M.; Ausschnitt, Christopher P.; Vukkadala, Pradeep; Veeraraghavan, Sathish; Sinha, Jaydeep K.
A design and performance evaluation is presented for the LANDSAT D attitude control system (ACS). Control and configuration of the gimballed Ku-band antenna system for communication with the tracking and data relay satellite (TDRS). Control of the solar array drive considered part of the ACS is also addressed.
Iwens, R. P.; Bernier, G. E.; Hofstadter, R. F.
In this lesson, students analyze land cover change in order to help them grasp the extent, significance, and consequences of land cover change; and to introduce them to the perspective of space-based Earth observations. Students learn to identify kinds of land cover (such as roads, fields, urban areas, and lakes) in Landsat satellite images. They decide which land cover types allow the passage of water into the soil (pervious) and which types do not allow it (impervious). They consider some effects of increasing impervious surface area on ecosystem health. Students then make land cover maps using two Landsat satellite images taken about a decade apart, and quantify the change of land cover from pervious to impervious surface. They also make predictive maps of what they think the nature and extent of land cover change in the area will be in the year 2025, and speculate about the consequences for the availability of water for people and ecosystems. Students justify in writing their predictive maps and their thoughts about the consequences of change. This activity uses Landsat images of Phoenix, Arizona; links are also provided for finding Landsat images of other cities.
A digital resampling technique for LANDSAT data is reported that incorporates a deconvolution concept to minimize spatial and radiometric degradation of data during resampling for geometric correction. A quantitative comparison of cubic convolution and digital restoration methods establishes the latter as the superior technique.
Shah, N. J.; Wilson, C. L.
A lunar observation by Landsat could provide improved radiometric and geometric calibration of both the Thematic Mapper and the Multispectral Scanner in terms of absolute radiometry, determination of the modulation transfer function, and sensitivity to scattered light. A pitch of the spacecraft would be required. -Authors
Kieffer, H.H.; Wildey, R.L.
This NASA page shows before and after pictures taken by Landsat 7's Enhanced Thematic Mapper Plus (ETM+) instrument of a part of the coast of Sumatra, Indonesia. The images show that the scale of the tsunami's impact can be seen from space.
This report provides results of an independent assessment of the horizontal geopositional accuracy of Earth Satellite (EarthSat) Corporation's GeoCover orthorectified Landsat Multispectral Scanner (MSS) imagery. This imagery was purchased through NASA's Earth Science Enterprise (ESE) Scientific Data Purchase (SDP) program.
Smith, Charles M.
This report provides the results of two independent evaluations, an absolute and a relative assessment, of the geopositional accuracy of the Earth Satellite (EarthSat) Corporation's GeoCover orthorectified Landsat Enhanced Thematic Mapper Plus (ETM+) imagery. This imagery was purchased through NASA's Earth Science Enterprise (ESE) Scientific Data Purchase (SDP) program.
Smith, Charles M.
Information on the use of LANDSAT data by Argentina is presented. Details on a Swedish satellite to be completed in 1984 and to be called VIKING are reported. Attempts to contact other civilizations in space by the use of radiotelescopes are discussed.
Wayne, D. L.; Bravo, V.
The effects of a glacially enriched zone of trace elements on soils and vegetation in the Thetford Mines area of Quebec were investigated using ground information plus digital Multispectral Scanner (MSS) data from airborne and Landsat sensors. The enriched zone was developed during the last glaciation when a southeastward flowing glacier eroded and dispersed an ultrabasic outcrop that had anomalous levels of Ni, Cu, Co, Cr, Mg and Fe. The dispersal train of enriched trace elements was detectable over an area at least 70 × 15 km `down-ice' from the outcrop. In this zone total Ni concentrations in the soil ranged from background levels of 10 ppm to levels in excess of 1800 ppm. The dominant tree species, Abies balsamea (balsam fir) and Picea glauca (white spruce) reflect the soil anomaly with higher concentrations of trace elements in their tissue and lower concentrations of chlorophyll. An unsupervised enhancement of Landsat imagery showed that a tonal discontinuity was caused by a vegetation segregation related to the heavy metal enrichment soils. A detailed study based on Landsat MSS data was able to establish regional patterns of chlorophyll production by certain plant species closely related to the ultrabasic dispersal train. Multi-channel airborne MSS data confirmed the Landsat soil-plant patterns.
Belanger, J. R.; Rencz, A. N.
Relative spectral response data for the multispectral scanner subsystems (MSS) to be flown on LANDSAT-D and LANDSAT-D backup, the protoflight and flight models, respectively, are presented and compared to similar data for the Landsat 1,2, and 3 subsystems. Channel-bychannel (six channels per band) outputs for soil and soybean targets were simulated and compared within each band and between scanners. The two LANDSAT-D scanners proved to be nearly identical in mean spectral response, but they exhibited some differences from the previous MSS's. Principal differences between the spectral responses of the D-scanners and previous scanners were: (1) a mean upper-band edge in the green band of 606 nm compared to previous means of 593 to 598 nm; (2) an average upper-band edge of 697 nm in the red band compared to previous averages of 701 to 710 nm; and (3) an average bandpass for the first near-IR band of 702-814 nm compared to a range of 693-793 to 697-802 nm for previous scanners. These differences caused the simulated D-scanner outputs to be 3 to 10 percent lower in the red band and 3 to 11 percent higher in the first near-IR band than previous scanners for the soybeans target. Otherwise, outputs from soil and soybean targets were only slightly affected. The D-scanners were generally more uniform from channel to channel within bands than previous scanners.
Markham, B. L. (principal investigator); Barker, J. L.
Change detection techniques were used to pinpoint differences in the multispectral band scanners on LANDSAT 2, 3, and 4 satellites. The method of analysis was to co-register 512 by 512 pixel subwindows for all data pairs followed by scattergram generation and analysis. In all cases, the LANDSAT-4 data were used as the base to which other images were registered. There appear to be no major problems preventing use of LANDSAT-4 MSS with previous MSS sensors for charge detection, provided the interference noise can be removed or minimized. This noise may result in detection of spurious changes, as well as affect other uses of the data, including image classification. Analysis of dark (water and forests), rather than light features will be most impacted because the noise will form a higher percentage of the total response at low DN values. Any data normalizations for change detection should be based upon the data, rather than solely upon calibration information. While the observed relative radiometric transfer function between LANDSAT 3 and 4 was approximately as predicted, there were still significant deviations. Normalizing based upon data content also can have the advantage of allowing simultaneous normalization of the atmosphere as well as the radiometry.
Likens, W. C.; Wrigley, R. C.
The applications of forest clearcut maps derived from LANDSAT data are dicussed. Such maps provide harvest location information useful in general management and indicate the stage of regrowth which helps determine timber stand improvement practices. The clearcut maps are also used in fire control planning and in determining wildlife habitats.
Bryant, E.; Sutherland, K.
We develop a forest typology system based on dynamic vegetation approach and apply it to the analysis of the forest type distribution for several test areas in Siberia, aiming at capability of mapping whole Siberian forests based on Landsat data. Test region locations are: two in West Siberian middle taiga (Laryegan and Nyagan), one in Central Siberia and one in East Siberia near Yakutsk. The ground truth data are based on analysis of the field survey, forest inventory data from the point of view of the successional forest type classification. Supervised classification was applied to the areas covered with analysis of the ground truth and inventory data, using several limited area maps and vegetation survey transects published in literature. In Laryegan basin the upland forest areas are dominated (as climax forest species) by Scots pine on sandy soils and Siberian pine with presence of fir and spruce on the others. Those types are separable using Landsat spectral data alone. In the permafrost area around Yakutsk the most widespread succession type is birch to larch succession. Three stages of the birch to larch succession are detectable from Landsat image. When Landsat data is used in both West and East Siberia, distinction between deciduous broad-leaved species (birch, aspen, and willow) is difficult due to similarity in spectral signatures. Same problem exist for distinguishing between dark coniferous species (Siberian pine, fir and spruce). Image classification can be improved by applying landscape type analysis, such as separation into floodplain, terrace, sloping hills. Additional layers of information seem to be a promising way to complement Landsat data, including SAR-based biomass maps and terrain data
Maksyutov, S. S.; Sedykh, V.; Kleptsova, I.; Frolov, A.; Silaev, A.; Kuzmenko, E.; Farber, S.; Kuzmik, N.; Sokolov, V. A.; Fedorov, A.; Nikolaeva, S.
Landsat 7 ETM+ provides an opportunity to extend the area and frequency with which we are able to monitor the Earth's surface with fine spatial resolution data. To take advantage of this opportunity it is necessary to move beyond the traditional image-by-image approac...
One strategy to tackle the complexity and scalability issue in large-scale mobile ad hoc networks (MANETs) is to use extra layers of abstraction. A common tactic is to group the nodes in the network into clusters. The clusters and the paths between them constitute an extra layer of overlay abstraction. To maintain the overlay structure, a head node is often
Amit Banerjee; Chung-ta King; Hung-chang Hsiao
1 Conjoining Speeds up Information Diffusion in Overlaying Social-Physical Networks Osman Yagan, junshan.zhang, email@example.com Abstract--We study the diffusion of information in an overlay- ing social-physical network. Specifically, we consider the following set-up: There is a physical information network where
, Akhilesh Saxena, Sudeept Bhatnagar, Suman Banerjee, Rauf Izmailov Abstract-- We present SPIDER Â a system, SPIDER uses an overlay structure composed of dedicated Transit Nodes (TNs). The data transport mechanism in SPIDER leverages this overlay structure to provide a coordinated approach that minimizes the maximum time
Combining Computer and Manual Overlays-- Willamette River Greenway Study1 Asa Hanamoto and Lucille of the Visual Resource, Incline Village, Nevada, April 23-25, 1979. 2/ Principal, and Staff Member, Royston computer mapping with manual overlays. An example of its use is the Willamette River Greenway Study
Standiford, Richard B.
In this paper, we describe an ongoing effort to define com- mon APIs for structured peer-to-peer overlays and the key abstractions that can be built on them. In doing so, we hope to facilitate independent innovation in overlay pro- tocols, services, and applications, to allow direct experi- mental comparisons, and to encourage application devel- opment by third parties. We provide
Frank Dabek; Ben Y. Zhao; Peter Druschel; John Kubiatowicz; Ion Stoica
OMAN - A Management Architecture for P2P Service Overlay Networks Adriano Fiorese1,2 , Paulo Sim Overlay Net- works (SON). The architecture, named OMAN, takes into account the formation of the P2P SON as pointing the overall potential of the OMAN archi- tecture. Keywords:Services Management, P2P, Service
Overlay text brings important semantic clues in video content analysis such as video information retrieval and summarization, since the content of the scene or the editor's intention can be well represented by using inserted text. Most of the previous approaches to extracting overlay text from videos are based on low-level features, such as edge, color, and texture information. However, existing methods experience difficulties in handling texts with various contrasts or inserted in a complex background. In this paper, we propose a novel framework to detect and extract the overlay text from the video scene. Based on our observation that there exist transient colors between inserted text and its adjacent background, a transition map is first generated. Then candidate regions are extracted by a reshaping method and the overlay text regions are determined based on the occurrence of overlay text in each candidate. The detected overlay text regions are localized accurately using the projection of overlay text pixels in the transition map and the text extraction is finally conducted. The proposed method is robust to different character size, position, contrast, and color. It is also language independent. Overlay text region update between frames is also employed to reduce the processing time. Experiments are performed on diverse videos to confirm the efficiency of the proposed method. PMID:19095537
Kim, Wonjun; Kim, Changick
Wafer based aberration metrology for lithographic systems using overlay measurements on targets projection system from wafer metrology data. For this, new types of phase-shift gratings (PSG) are introduced metrology tool. In this way, the overlay error can be used as a measurand based on which the phase
Exactly computing map overlays using rational numbers Salles V. G. MaghalÃ£es and W Randolph by representing coordinates as rational numbers. Now, intersections have no roundoff errors. Rational numbers for different kinds of soil. This paper presents Rat-overlay, an algorithm that uses rational numbers to perform
Franklin, W. Randolph
It is expected that routing on long-haul optical networks will migrate from the electronic domain to the optical]. The system consists of a method for overlaying information onto a payload stream, and a low cost decoding is that of overlaying a low- rate multiple access channel on a high-rate payload channel in a very specific way
Recently, overlay network-based collaborative applications such as instant messaging, content sharing, and Internet telephony are becoming increasingly popular. Many of these applications rely upon data-replication to achieve better performance, scalability, and reliability. However, replication entails various costs such as storage for holding replicas and communication overheads for ensuring replica consistency. While simple rule-of-thumb strategies are popular for managing the cost-benefit tradeoffs of replication, they cannot ensure optimal resource utilization. This paper explores a multi-objective optimization approach for replica management, which is unique in the sense that we view the various factors influencing replication decisions such as access latency, storage costs, and data availability as objectives, and not as constraints. This enables us to search for solutions that yield close to optimal values for these parameters. We propose two novel algorithms, namely multi-objective Evolutionary (MOE) algorithm and multi-objective Randomized Greedy (MORG) algorithm for deciding the number of replicas as well as their placement within the overlay. While MOE yields higher quality solutions, MORG is better in terms of computational efficiency. The paper reports a series of experiments that demonstrate the effectiveness of the proposed algorithms.
Al-Haj Hassan, Osama; Ramaswamy, Lakshmish; Miller, John; Rasheed, Khaled; Canfield, E. Rodney
For reasons of economy, hydrogenation pressure vessels of heavy wall sections are fabricated by cladding with one or more layers of austenitic stainless steel on the inside of the vessel wall. Submerged Arc Welding with strip-electrode technology is used in this process because of its ability to combine excellent deposit properties and controllable penetration with high deposition rates. However, hydrogen-related disbonding of the clad-overlay is a problem remaining in the use of the composite pressure vessels in petrochemical industries. One of the major factors contributing to the disbonding is the microstructure developed during solidification of the weld metal. It is unclear what kind of microstructure is most susceptible to disbonding and how the microstructure develops. Marshall and Lazor et al. believed that martensitic structures were the culprit for the initiation of disbonding. Ohnishi et al. concluded from their investigation that a layer of martensite adjacent to the fusion line would reduce the disbonding. Recently, Godden et al. found that a so-called Type 2 grain boundary was the most susceptible structure to the disbonding, but the mechanism is not clear. This study investigated the microstructures along the interface between overlays and base steel and established the mechanism of the formation of crack-susceptible microstructures.
Wu, Yunjian; Patchett, B.M.; Bicknell, C. (Univ. of Alberta, Edmonton, Alberta (Canada))
In this publication, the contributors to in-field overlay metrology uncertainty have been parsed and quantified on a back end process and compared with results from a previous front end study1. Particular focus is placed on the unmodeled systematics, i.e. the components which contribute to residuals in a linear model after removal of random errors. These are the contributors which are often the most challenging to quantify and are suspected to be significant in the model residuals. The results show that in both back and front end processes, the unmodeled systematics are the dominant residual contributor, accounting for 60 to 70% of the variance, even when subsequent exposures are on the same scanner. A higher order overlay model analysis demonstrates that this element of the residuals can be further dissected into correctible and non-correctible high order systematics. A preliminary sampling analysis demonstrates a major opportunity to improve the accuracy of lot dispositioning parameters by transitioning to denser sample plans compared with standard practices. Field stability is defined as a metric to quantify the field to field variability of the intrafield correctibles.
Adel, Mike; Frommer, Aviv; Kassel, Elyakim; Izikson, Pavel; Leray, Philippe; Schulz, Bernd; Seltmann, Rolf; Busch, Jens
Overlay metrology performance as Total Measurement Uncertainty (TMU), design rule compatibility, device correlation and measurement accuracy are been challenged at 2x nm node and below. Process impact on overlay metrology becoming critical, and techniques to improve measurement accuracy becomes increasingly important. In this paper, we present an innovative methodology for improving overlay accuracy. A propriety quality metric, Qmerit, is used to identify overlay metrology measurement settings with least process impacts and reliable accuracies. Using the quality metric, an innovative calibration method, ASC (Archer Self Calibration) is then used to remove the inaccuracies. Accuracy validation can be achieved by correlation to reference overlay data from another independent metrology source such as CDSEM data collected on DCM (Device Correlated Metrology) hybrid target or electrical testing. Additionally, reference metrology can also be used to verify which measurement conditions are the most accurate. In this paper we bring an example of such use case.
Tzai, Wei-Jhe; Hsu, Simon C. C.; Chen, Howard; Chen, Charlie; Pai, Yuan Chi; Yu, Chun-Chi; Lin, Chia Ching; Itzkovich, Tal; Yap, Lipkong; Amit, Eran; Tien, David; Huang, Eros; Kuo, Kelly T. L.; Amir, Nuriel
This paper examines the strain response of typical HMA overlays above jointed PCC slabs prone to bottom-up reflective cracking. The occurrence of reflective cracking under the combined effect of traffic and environmental loading significantly reduces the design life of the HMA overlays and can lead to its premature failure. In this context, viscoelastic material properties combined with cyclic vehicle loadings and pavement temperature distribution were implemented in a series of FE models in order to study the evolution of horizontal tensile and shear strains at the bottom of the HMA overlay. The effect of several design parameters, such as subbase and subgrade moduli, vehicle speed, overlay thickness, and temperature condition, on the horizontal and shear strain response was investigated. Results obtained show that the rate of horizontal and shear strain increase at the bottom of the HMA overlay drop with higher vehicle speed, higher subgrade modulus, and higher subbase modulus. Moreover, the rate of horizon...
Ghauch, Ziad G
Craniofacial superimposition can provide evidence to support that some human skeletal remains belong or not to a missing person. It involves the process of overlaying a skull with a number of ante mortem images of an individual and the analysis of their morphological correspondence. Within the craniofacial superimposition process, the skull-face overlay stage just focuses on achieving the best possible overlay of the skull and a single ante mortem image of the suspect. Although craniofacial superimposition has been in use for over a century, skull-face overlay is still applied by means of a trial-and-error approach without an automatic method. Practitioners finish the process once they consider that a good enough overlay has been attained. Hence, skull-face overlay is a very challenging, subjective, error prone, and time consuming part of the whole process. Though the numerical assessment of the method quality has not been achieved yet, computer vision and soft computing arise as powerful tools to automate it, dramatically reducing the time taken by the expert and obtaining an unbiased overlay result. In this manuscript, we justify and analyze the use of these techniques to properly model the skull-face overlay problem. We also present the automatic technical procedure we have developed using these computational methods and show the four overlays obtained in two craniofacial superimposition cases. This automatic procedure can be thus considered as a tool to aid forensic anthropologists to develop the skull-face overlay, automating and avoiding subjectivity of the most tedious task within craniofacial superimposition. PMID:25447179
Campomanes-Álvarez, B Rosario; Ibáñez, O; Navarro, F; Alemán, I; Botella, M; Damas, S; Cordón, O
The Landsat Data Continuity Mission (LDCM) is being developed by NASA and USGS and is currently planned for launch in January 2013 . Once on-orbit and checked out, it will be operated by USGS and officially named Landsat-8. Two sensors will be on LDCM: the Operational Land Imager (OLI), which has been built and delivered by Ball Aerospace & Technology Corp (BATC) and the Thermal Infrared Sensor (TIRS), currently being built and tested at Goddard Space Flight Center (GSFC) with a planned delivery of Winter 2012. The OLI covers the Visible, Near-IR (NIR) and Short-Wave Infrared (SWIR) parts of the spectrum; TIRS covers the Thermal Infrared (TIR). This paper discusses only the OLI instrument and its pre-launch characterization; a companion paper covers TIRS.
Markham, Brian L.; Knight, Edward J.; Canova, Brent; Donley, Eric; Kvaran, Geri; Lee, Kenton; Barsi, Julia A.; Pedelty, Jeffrey A.; Dabney, Philip W.; Irons, James R.
The Chevron-Kenya oil license, acquired in 1972, covers an area at the north end of the Lamu Embayment. Immediately after acquisition, a photogeologic study of the area was made followed by a short field inspection. An interpretation of LANDSAT-1 images as a separate attempt to improve geological knowledge was completed. The method used in the image study, the multispectral characteristics of rock units and terrain, and the observed anomalous features as seen in the LANDSAT imagery are described. It was found that the study helped to define the relationship of the Lamu Embayment and its internal structure with surrounding regional features, such as the East Africa rifting, the Rudolf Trough, the Bur Acaba structural ridge, and the Ogaden Basin.
Miller, J. B.
The history of the Landsat project is discussed in terms of three historical phases, each characterized by a dominant problem. From 1964 to 1967, the challenge was to develop interagency cooperation and to achieve consensus on basic plans for the satellite. Between 1968 and 1971, the cooperating agencies had to persuade the Bureau of the Budget to provide funding for the project. Since 1972, the challenge to NASA has been to encourage applications of the Landsat data and plan the shift from an experimental program to an operational one. The tension between experimental and operational goals has run through all these phases, and the conflicts between agencies is detailed, as well as the interaction between technological and political systems.
Mach, P. E.
The LDCM's Landsat 8 (L8), planned for launch in February 2013, is the latest satellite in the 40 year history of the Landsat program. The satellite will have two imagers: the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). The data from both sensors will be processed and combined into the final Level 1 Terrain (L1T) standard product by the Landsat Product Generation System (LPGS) at the USGS Earth Resources Observation and Science (EROS). Landsat 8 products will nominally have 11 image bands; however, products will still be created if OLI only, or TIRS only collections are acquired. The LPGS is designed to create L1T products from Level 0 data by merging OLI and TIRS outputs and performing systematic radiometric and geometric corrections, followed by precision and terrain corrections that include Ground Control Points (GCP), and a Digital Elevation Model (DEM) for topographic accuracy. Scenes that have a quality score of 9 or greater and a percent cloud cover less than 40 will be automatically processed. In addition, any archived scene, regardless of cloud cover, can be requested for processing through USGS EROS clients, GloVis or Earth Explorer. While most data will be processed as Level L1T, some scenes will not have ground control or elevation data necessary for precision or terrain correction, respectively. In these cases, the best level of correction will be applied (Level 1G-systematic or Level 1Gt-systematic terrain). The standard Level 1T products will contain scaled Top of Atmosphere (TOA) reflectance data, only for OLI. The conversion between radiance and reflectance within radiometric processing (L1R) will be performed using the band specific coefficients that are proportional to the respective exoatmospheric solar irradiances and the Earth-Sun distance for the scene's acquisition day. The TIRS data will contain scaled at-sensor radiances and no at-sensor brightness temperature or emissivity conversions are planned. For users that prefer uncorrected data a Level 0 Reformatted Product (L0Rp) product will be available. The standard L1T product for L8 will be a 16-bit, north up Universal Transverse Mercator (UTM) projection, Cubic Convolution (CC) resampled, GeoTIFF file. The delivered tar file contains eight 30-meter OlI multispectral bands, one 15-meter OLI Panchromatic band, two TIRS thermal bands, a Quality Band (QB), a metadata file, and an Angle Band. The QB is a file that contains quality statistics from the image data and cloud mask for the scene. The metadata file contains information about the product ordered and is essential for the end user to know how that product was processed. The Angle Band is a binary image file that contains the solar angle information for the scene data collected. The L1T reflectance product bands will be generated with no sun angle correction applied. The angle band will enable an optional TOA reflectance calculation using the sun angles specific to each image pixel. This method was chosen to maintain continuity with Landsat products while allowing the users that require a per pixel sun angle correction to have that capability. An example of a L8 product can be downloaded from the Landsat website located at: http://landsat.usgs.gov/LDCM_DataProduct.php. The sample L8 product was created using Landsat 7 data projected onto a L8 grid and processed to LDCM data product specifications.
Micijevic, E.; Hayes, R.
Agriculture, which occupies a vital position in the economy of the State of California, depends crucially on the available water. The California Department of Water Resources (DWR) is, therefore, greatly concerned with the total water requirements for agricultural applications. In view of the limitations of an area-limited, single-date survey system, the DWR has been cooperating with NASA and the University of California in a study of the applicability of Landsat imagery and digital data as an aid in making decisions concerning the management of water resources. Attention is given to a statewide inventory of irrigated land, computer-assisted estimation and mapping of irrigated land, and a crop type analysis using Landsat digital data.
Wall, S. L.; Thomas, R. W.; Brown, C. E.; Bauer, E. H.
Currently, inventory of California's irrigated lands is performed on a seven year cycle. Since 1975, the University of California in cooperation with NASA and the California Department of Water Resources has been developing and testing techniques to utilize a Landsat based remote sensing system to produce statewide estimates in a single year. The proposed system utilizes multiphase sampling, stratification and multitemporal Landsat imagery to produce the estimate. Early research concentrated on regional estimates to develop the techniques. This year, an inventory of the entire state of California is being performed. In addition, research on the utilization of digital analysis for estimating irrigated acreage and the determination of specific crop types (manual and digital analysis) is also underway.
Wall, S. L.; Thomas, R. W.; Tinney, L. R.
No uranium deposits are known in the Trabzon, Turkey region, and consequently, exploration criteria have not been defined. Nonetheless, by analogy with uranium deposits studied elsewhere, exploration guides are suggested to include dense concentrations of linear features, lineaments -- especially with northwest trend, acidic plutonic rocks, and alteration indicated by limonite. A suite of digitally processed images of a single Landsat scene served as the image base for mapping 3,376 linear features. Analysis of the linear feature data yielded two statistically significant trends, which in turn defined two sets of strong lineaments. Color composite images were used to map acidic plutonic rocks and areas of surficial limonitic materials. The Landsat interpretation yielded a map of these exploration guides that may be used to evaluate relative uranium potential. One area in particular shows a high coincidence of favorable indicators.
The author has identified the following significant results. LANDSAT spatial resolution was estimated to be adequate, but barely so, for the purpose of detailed assessment of rice or site status. This was due to the spatially fine grain, heterogenous nature of most rice areas. Use of two spectral bands of digital data (MSS 5 and MSS 6 or 7) appeared to be adequate for site recognition and gross site status assessment. Spectral/temporal signatures were found to be more powerful than spectra signatures alone and virtually essential for most analyses of rice growth and rice sites in the Philippine environment. Two band, two date signatures were estimated to be adequate for most purposes, although good results were achieved using one band two- or four-date signatures. A radiometric resolution of 64 levels in each band was found adequate for the analyses of LANDSAT digital data for site recognition and gross site or rice growth assessment.
Mcnair, A. J.; Heydt, H. L.; Liang, T.; Levine, G. (principal investigators)
A critical problem involved in quantitative multi-temporal sensing of the physical processes with Landsat is the fact that variations in the spectral signatures for a given target of interest result from a combined effect of target properties and the environmental factors such as sun angles, atmospheric conditions, etc. at the time of an overpass. In an attempt to solve the problem, a transformation procedure is developed to remove the environmental effects from the MSS radiance data. Mathematical derivation of the transformation procedure is elaborated and an example of testing the procedure is illustrated using suspended sediments reflectance data obtained by Landsat MSS during four different overpasses over the lower Mississippi River valley.
Kim, S. T.; Smith, D. W.
Data collected on the spectral characteristics of the LANDSAT-4 and LANDSAT-4 backup thematic mapper instruments, the protoflight (TM/PF) and flight (TM/F) models, respectively, are presented and analyzed. Tests were conducted on the instruments and their components to determine compliance with two sets of spectral specifications: band-by-band spectral coverage and channel-by-channel within-band spectral matching. Spectral coverage specifications were placed on: (1) band edges--points at 50% of peak response, (2) band edge slopes--steepness of rise and fall-off of response, (3) spectral flatness--evenness of response between edges, and (4) spurious system response--ratio of out-of-band response to in-band response. Compliance with the spectral coverage specifications was determined by analysis of spectral measurements on the individual components contributing to the overall spectral response: filters, detectors, and optical surfaces.
Markham, B. L.; Barker, J. L.
The Boreal Ecosystem-Atmosphere Study (BOREAS) Remote Sensing Science (RSS)-8 team utilized Landsat Thematic Mapper (TM) images to perform mapping of snow extent over the Southern Study Area (SSA). This data set consists of two Landsat TM images that were used to determine the snow-covered pixels over the BOREAS SSA on 18 Jan 1993 and on 06 Feb 1994. The data are stored in binary image format files. The RSS-08 snow map data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).
Hall, Dorothy; Chang, Alfred T. C.; Foster, James L.; Chien, Janeet Y. L.; Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Smith, David E. (Technical Monitor)
Landsat data have been investigated extensively to determine crop types and acreage. However, confounding site factors have been found to reduce accuracy. Soils data in a small, contiguous area in southeast South Dakota were used to stratify Landsat data. A June 5 and July 29 CCT were used in a statistical analysis of corn training data. Significant soil parameters causing differences in study area soils were slope and parent material. Implication of the results is that, in this region, stratification of CCT data along parent material boundaries would improve corn classification accuracy. Research expanding on the interaction of soils and crops is both in progress and scheduled for additional studies in east central South Dakota.
Dalsted, K. J.; Worcester, B. K.; Devries, M. E.
We report on the formation of a chemically bound 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) monolayer on modified Au and silica surfaces, and changes in the organization of the interfacial lipid layer associated with immersion in aqueous solution. We have studied the interface using steady state and time resolved fluorescence spectroscopy, water contact angle and optical ellipsometry measurements, and electrochemical methods. Our data reveal that the DMPC adlayer in contact with air forms a relatively well organized interface that mediates the rotational motion of perylene. In the presence of an aqueous overlayer, perylene reorientation becomes more rapid, consistent with a reduction in the organization of the interfacial lipid adlayer. One implication of this finding is that the interfacial adlayer is less than a uniform monolayer, which is confirmed by electrochemical data. Our data underscore the importance of water in mediating the organization of interfacial lipid adlayers. PMID:22995467
Baumler, S M; Blanchard, G J
Overlay metrology is a very demanding image processing application; current applications are achieving dynamic precision of one hundredth of a pixel or better. As such it requires an accurate image acquisition system, with minimal distortions. Distortions can be physical (e.g. pixel size / shape) or electronic (e.g. clock skew) in nature. They can also affect the image shape, or the gray level intensity of individual pixels, the former causing severe problems to pattern recognition and measurement algorithms, the latter having an adverse effect primarily on the measurement itself. This paper considers the artifacts that are present in a particular analogue camera, with a discussion on how these artifacts translate into a reduction of overlay metrology performance, in particular their effect on precision and tool induced shift (TIS). The observed effects include, but are not limited to, banding and interlacing. This camera is then compared to two digital cameras. The first of these operates at the same frame rate as the analogue camera, and is found to have fewer distortions than the analogue camera. The second camera operates with a frame rate twice that of the other two. It is observed that this camera does not exhibit the distortions of the analogue camera, but instead has some very specific problems, particularly with regards to noise. The quantitative data on the effect on precision and TIS under a wide variety of conditions, is presented. These show that while it is possible to achieve metrology-capable images using an analogue camera, it is preferable to use a digital camera, both from the perspective of overall system performance, and overall system complexity.
Rigden, Timothy C.; Soroka, Andrew J.; Binns, Lewis A.
As a design rule shrink down aggressively, various RETs (Resolution Enhancement Technology) have been developed to extend the resolution limits of lithography. Until now, next generation lithography has been focused on EUV technology. But no one can assure when EUV will be implemented. So, we must develop new technology with current immersion tool to catch up with aggressive design rule. One of those is DPT (Double Patterning Technology), however there are also many challenges to overcome such as patterning, overlay, hard mask etch and so on. The most critical issue would be overlay, because it affects CD (Critical dimension) uniformity directly. Therefore, overlay control is very important between 1 st DP layer and 2 nd DP layer. We utilized ArF immersion scanners for this experiment. In this paper, DP process flow, hard mask film dependency, align method dependency, efforts of new align key design and direct align analysis in DP overlay will be reported to understand and get better overlay accuracy than tool specification. It is needed to be verified that how much they take an effect on improving the DP overlay. Continuously we can conclude that most efforts in DPT should be focused on overlay control issue.
Ma, Won-kwang; Kang, Jung-hyun; Lim, Chang-moon; Kim, HyeongSoo; Moon, Seung-chan; Lalbahadoersing, Sanjay; Oh, Seung-chul
The overlay metrology budget is typically 1/10 of the overlay control budget resulting in overlay metrology total measurement uncertainty requirements of 0.57 nm for the most challenging use cases of the 32nm technology generation. Theoretical considerations show that overlay technology based on differential signal scatterometry (SCOL TM) has inherent advantages, which will allow it to achieve the 32nm technology generation requirements and go beyond it. In this work we present results of an experimental and theoretical study of SCOL. We present experimental results, comparing this technology with the standard imaging overlay metrology. In particular, we present performance results, such as precision and tool induced shift, for different target designs. The response to a large range of induced misalignment is also shown. SCOL performance on these targets for a real stack is reported. We also show results of simulations of the expected accuracy and performance associated with a variety of scatterometry overlay target designs. The simulations were carried out on several stacks including FEOL and BEOL materials. The inherent limitations and possible improvements of the SCOL technology are discussed. We show that with the appropriate target design and algorithms, scatterometry overlay achieves the accuracy required for future technology generations.
Leray, Philippe; Cheng, Shaunee; Kandel, Daniel; Adel, Michael; Marchelli, Anat; Vakshtein, Irina; Vasconi, Mauro; Salski, Bartlomiej
The physical interpretation of the spectral-temporal structure of LANDSAT data can be conveniently described in terms of a graphic descriptive model called the Tassled Cap. This model has been a source of development not only in crop-related feature extraction, but also for data screening and for haze effects correction. Following its qualitative description and an indication of its applications, the model is used to analyze several feature extraction algorithms.
Kauth, R. J.; Lambeck, P. F.; Richardson, W.; Thomas, G. S.; Pentland, A. P. (principal investigators)
A cooperative program between the Wisconsin Department of Natural Resources and the University of Wisconsin for the assessment, with Landsat data, of the trophic status of all the significant inland lakes in Wisconsin is described. The analysis technique is a semiautomatic data acquisition and handling system which, in conjunction with an analytical categorization scheme, can be used for classifying inland lakes into one of seven categories of eutrophication and one of four problem types.
Scarpace, F. L.; Fisher, L. T.
A study has been carried out to develop a photo-optical technique by which Landsat imagery can be used to monitor trophic states of lakes. The proposed technique uses a single number to characterize the trophic state, and a feature within the satellite scene is used as an internal standard for comparison of the lakes in time. By use of the technique it is possible to assess in retrospect the trophic state of each individual lake.
Welby, C. W.; Witherspoon, A. M.; Holman, R. E., III
This preliminary report examines those radiometric characteristics of the Landsat 4 Thematic Mapper (TM) that can be established without absolute calibration of spectral data. Analysis is based largely on radiometrically raw (B type) data of three daytime and two nighttime scenes; in most scenes, a set of 512 lines were examined on an individual-detector basis. Subscenes selected for uniform-radiance were used to characterize subtle radiometric differences and noise problems.
Kieffer, Hugh H.; Eliason, Eric M.; Chavez, Pat S., Jr.
Various computer enhancement and data extraction systems using LANDSAT data were assessed and used to complement a continuing geologic mapping program. Interactive digital classification techniques using both the parallel-piped and maximum-likelihood statistical approaches achieve very limited success in areas of highly dissected terrain. Computer enhanced imagery developed by color compositing stretched MSS ratio data was constructed for a test site in northwestern Saudi Arabia. Initial results indicate that several igneous and sedimentary rock types can be discriminated.
Blodget, H. W.; Brown, G. F.; Moik, J. G.
The characteristics of the TIROS, GOES, DMSP and LANDSAT systems of satellites are described. The data listed for each system are altitude of orbit, inclination/position, orbit type, orbits per day, expected operational lifetime and the sensor systems. The sensor systems are described as to wavelength of each channel, resolution, field of view and other pertinent information. Data information such as availability rate, collection method, primary use/application and how to obtain additional information is also given.
Gray, T. I., Jr.; Mccrary, D. G.; Armstrong, T. A. (principal investigators)
Hardware, systems, and subsystems for the multimission modular spacecraft used for LANDSAT 4 are described and depicted in block diagrams and schematics. Components discussed include the modular attitude control system; the communication and data handling subsystem; the narrowband tape recorder; the on-board computer; the propulsion module subsystem; the signal conditioning and control unit; the modular power subsystem; the solar array drive and power transmission assembly; the power distribution unit; the digital processing unit; and the wideband communication subsystem.
The Landsat Data Continuity Mission (LDCM), a joint NASA and USGS mission, is scheduled for launch in December, 2012. The LDCM instrument payload will consist of the Operational Land Imager (OLI), provided by Ball Aerospace and Technology Corporation (BATC} under contract to NASA and the Thermal Infrared Sensor (TIRS), provided by NASA's Goddard Space Flight Center (GSFC). This paper outlines the design of the TIRS instrument and gives an example of its application to monitoring water consumption by measuring evapotranspiration.
Reuter, Dennis; Richardson, Cathy; Irons, James; Allen, Rick; Anderson, Martha; Budinoff, Jason; Casto, Gordon; Coltharp, Craig; Finneran, Paul; Forsbacka, Betsy; Hale, Taylor; Jennings, Tom; Jhabvala, Murzy; Lunsford, Allen; Magnuson, Greg; Mills, Rick; Morse, Tony; Otero, Veronica; Rohrbach, Scott; Smith, Ramsey; Sullivan, Terry; Tesfaye, Zelalem; Thome, Kurtis; Unger, Glenn; Whitehouse, Paul
A wide spectrum of technology pertaining to the inventory of crops using LANDSAT without in situ training data is addressed. Methods considered include Bayesian based through-the-season methods, estimation technology based on analytical profile fitting methods, and expert-based computer aided methods. Although the research was conducted using U.S. data, the adaptation of the technology to the Southern Hemisphere, especially Argentina was considered.
Horvath, R.; Cicone, R. C.; Malila, W. A. (principal investigators)
Thresholded ratio images from Landsat TM4 \\/ TM5 provide a simple, robust and quite accurate method for classification of clean glacier ice. Automatic retrieval of glacier inventory data is possible by means of GIS-based processing in combination with a DEM of appropriate accuracy. In view of the USGS-led project `Global Land Ice Monitoring from Space' (GLIMS) which aims at a
F. Paul; A. Kaeaeb; M. Maisch; M. Hoelzle; W. Haeberli
These images are compressed versions of high definition television (HDTV) images showing how Landsat data, which spans a very broad swatch of the electromagnetic spectrum, can be turned into images. The TIFF versions of these images are full resolution HDTV frames (1920 x 1080). All images have the HDTV standard aspect ratio (16:9). The Thematic Mapper (TM) on Landsat 4 and 5 observes reflected sunlight from the Earth all the way from blue in the visible part of the electromagnetic spectrum to shortwave infrared well beyond the ability of the human eye to percieve. The TM instrument also can observe infrared radiation actively emitted by the Earth from thermal infrared radiation. Landsat 7 carries an improved version of the TM instrument, called ETM+. In addition to 7 channels of spectral data collected by the older TM instruments, ETM+ can observe in a special panchromatic band spanning the entire visible spectrum at twice the resolution of the TM bands (15 meter resolution instead of 30 meters). The ETM+ also has a major improvement in the resolution of the thermal band (60 meter resolution instead of 160 meters). A standard way to create images from raw Landsat TM and ETM+ data is to display a single band as a primary color, then combine different bands to create a full color image. Images shown here demonstrate combining three bands to make a color image using TM bands 5, 4, & 2, which covers a very broad range of the TM's spectral coverage. It is also shown in combination with a digital elevation model. Terrain data is shown with vertical features exagerated by a factor of three to emphasize details.
Allen, Jesse; Williams, Darrel
The Landsat Data Continuity Mission (LDCM) is next in the series of Landsat Earth remote sensing missions. At this writing, both the Thematic Mapper on the Landsat 5 spacecraft and the Enhanced Thematic Mapper Plus on the Landsat 7 spacecraft are producing routine Earth images, as part of a data set extending over three decades. The LDCM is required to continue this series of measurements. The LDCM Project has developed requirements for the data set to be produced by the LDCM sensor based on previous Landsat data, the proven technology from the Advanced Land Imager instrument flown on the EO-1 technology demonstration spacecraft, and on trade-offs made during the LDCM Formulation Phase. The unique nature of the LDCM government-commercial industry cooperative effort has resulted in a set of calibration and validation requirements intended to guarantee that the data from the commercially-owned LDCM sensor maintains the legacy of highly calibrated Landsat data.
Murphy-Morris, Jeanine E.; Irons, James R.; Markham, Brian L.; Barnes, Robert A.; Schweiss, Robert J.
Most land cover maps generated from Landsat imagery involve classification of a wide variety of land cover types, whereas some studies may only need spatial information on a single cover type. For example, we required a map of corn in order to estimate exposure to agricultural chemicals for an environmental epidemiology study. Traditional classification techniques, which require the collection and processing of costly ground reference data, were not feasible for our application because of the large number of images to be analyzed. We present a new method that has the potential to automate the classification of corn from Landsat satellite imagery, resulting in a more timely product for applications covering large geographical regions. Our approach uses readily available agricultural areal estimates to enable automation of the classification process resulting in a map identifying land cover as 'highly likely corn,' 'likely corn' or 'unlikely corn.' To demonstrate the feasibility of this approach, we produced a map consisting of the three corn likelihood classes using a Landsat image in south central Nebraska. Overall classification accuracy of the map was 92.2% when compared to ground reference data. ?? 2003 Elsevier B.V. All rights reserved.
Maxwell, S.K.; Nuckols, J.R.; Ward, M.H.; Hoffer, R.M.
Landsat-7 Enhanced Thematic Mapper+ (ETM+), launched in April 1999, and Landsat-5 Thematic Mapper (TM), launched in 1984, both have a single thermal band. Both instruments thermal band calibrations have been updated previously: ETM+ in 2001 for a pre-launch calibration error and TM in 2007 for data acquired since the current era of vicarious calibration has been in place (1999). Vicarious calibration teams at Rochester Institute of Technology (RIT) and NASA/Jet Propulsion Laboratory (JPL) have been working to validate the instrument calibration since 1999. Recent developments in their techniques and sites have expanded the temperature and temporal range of the validation. The new data indicate that the calibration of both instruments had errors: the ETM+ calibration contained a gain error of 5.8% since launch; the TM calibration contained a gain error of 5% and an additional offset error between 1997 and 1999. Both instruments required adjustments in their thermal calibration coefficients in order to correct for the errors. The new coefficients were calculated and added to the Landsat operational processing system in early 2010. With the corrections, both instruments are calibrated to within +/-0.7K.
Barsi, Julia A.; Markham, Brian L.; Schoff, John R.; Hook, Simon J.; Raqueno, Nina G.
Early season changes in optical depth change brightness, primarily along the soil line; and during crop development, changes in optical depth change both greenness and brightness. Thus, the existence of haze in the imagery could cause an unsuspecting analyst to interpret the spectral appearance as indicating an episodal event when, in fact, haze was present. The techniques for converting LANDSAT-3 data to simulate LANDSAT-2 data are in error. The yellowness and none such computations are affected primarily. Yellowness appears well correlated to optical depth. Experimental evidence with variable background and variable optical depth is needed, however. The variance of picture elements within a spring wheat field is related to its equivalent in optical depth changes caused by haze. This establishes the sensitivity of channel 1 (greenness) pixels to changes in haze levels. The between field picture element means and variances were determined for the spring wheat fields. This shows the variability of channel data on two specific dates, emphasizing that crop development can be influenced by many factors. The atmospheric correction program ATCOR reduces segment data from LANDSAT acquisitions to a common haze level and improves the results of analysis.
Johnson, W. R.; Sestak, M. L. (principal investigators)
Temporal variation in earth-atmosphere system reflectance in the 0.5-1.1 micron waveband was determined from Landsat MSS data for an area of arid rangeland in south-central New Mexico. Data were extracted from eight MSS scenes for the period 1973-1983, with four scenes from 1976. Maximum potential change between the extremes of rangeland degradation status was estimated to provide a benchmark for assessing the significance of the observed variations. Reflectance standardized for differences in sensor radiometric response by the Environmental Research Institute of Michigan coefficients increased significantly from 1973 to 1983, but standardization by Landsat Data Users Handbook coefficients resulted in little long-term change. Short-term (less than 1 year) variation was significant relative to maximum potential change. A sequence of three Landsat-2 scenes within one year showed a decrease in reflectance with increasing solar zenith angle. The effect of zenith angle on shading of the soil surface by plants was estimated and found to be about the same magnitude as the observed within-year variation in reflectance with solar zenith angle.
Musick, H. B.
The synoptic view of local and regional lineament patterns by Landsat is a useful mapping technique in areas considered to be well mapped as well as in poorly mapped areas. Image enhancement of digital Landsat data increases contrast and sharpness between geologic features and improves the recognition of subtle differences. Five enhancement techniques were applied to Landsat digital data for lineament detection for a portion of the structure in southeastern Oklahoma, specifically a 169 mi/sup 2/ area centered in the Ouachita Mountains. Of the five enhancement techniques evaluated (1) mean value of all four bands, (2) principal components, (3) band ratio, (4) histogram equalization, and (5) high-pass filter, the principal components analysis identified the greatest number of lineaments and the greatest total length of lineaments. All five techniques identified a significant amount of unique lineaments which were not found by any other technique; they agreed, however, in terms of the directions in which the lineaments were oriented. The unique lineaments identified by each technique were combined through a composite process to yield a lineament interpretation which exceeded the detection capability of the principal components enhancement.
Walsh, S.J.; Mynar, F. II
Procedures used to map residential land cover on the Orlando, Florida, Urban fringe zone are detailed. The NASA Bureau of the Census Applications Systems Verification and Transfer project and the test site are described as well as the LANDSAT data used as the land cover information sources. Both single-date LANDSAT data processing and multitemporal principal components LANDSAT data processing are described. A summary of significant findings is included.
Walthall, C. L.; Knapp, E. M.
The theory and application of remose sensing is reviewed with particular emphasis on the LANDSAT system. Main topics refer to the physical principles of remote sensing and visual/automatic analysis of LANDSAT data applied to natural resources surveying and monitoring. Case studies regarding remote sensing applications in forestry, soil mapping, land use, morphometric analysis, geomorphology, range management and assessment are discussed. Conclusive remarks appoint LANDSAT as a improving tool to overcome the lack of basic information related to natural resources inventory.
Dejesusparada, N. (principal investigator); Nday, I.
The LANDSAT analysis carried out as part of Ames Research Center's San Bernardino County Project, one of four projects sponsored by NASA as part of the California Integrated Remote Sensing System (CIRSS) effort for generating and utilizing digital geographic data bases, is described. Topics explored include use of data-base modeling with spectral cluster data to improve LANDSAT data classification, and quantitative evaluation of several change techniques. Both 1976 and 1979 LANDSAT data were used in the project.
Likens, W.; Maw, K.; Sinnott, D. (principal investigators)
The LANDSAT-4 mission has unique characteristics relative to previous LANDSAT missions. The spacecraft is new; the orbit is lower with a more frequent repeat cycle; and the ground processing facility consists of new hardware with different algorithms being applied. How some of these changes affect the character of the radiometric data quality is explored. Banding effects; radiometric differences between LANDSAT 3 and 4; and the woodgrain pattern observed visually in the images are considered.
Alford, W. L.; Imhoff, M. L.
EROS Data Center is evaluating the geodetic accuracy of Landsat-4 data from both the Multispectral Scanner (MSS) and Thematic Mapper (TM) processing systems. Geodetic accuracy is a measure of the precision of Landsat data registration to the Earth's figure. This paper describes a geodetic accuracy assessment of several MSS and TM scenes, based on the geodetic referencing information supplied on a standard Landsat 4 computer compatible tape.
Thormodsgard, J.M.; DeVries, D.J.
A two-inch Return Beam Vidicon (RBV) panchromatic two camera Subsystem, together with spare components was designed and fabricated for the LANDSAT-C Satellite; the basis for the design was the Landsat 1&2 RBV Camera System. The purpose of the RBV Subsystem is to acquire high resolution pictures of the Earth for a mapping application. Where possible, residual LANDSAT 1 and 2 equipment was utilized.
The integrated circuit (IC) manufacturing factories have measured overlay with conventional "box-in-box" (BiB) or "frame-in-frame" (FiF) structures for many years. Since UMC played as a roll of world class IC foundry service provider, tighter and tighter alignment accuracy specs need to be achieved from generation to generation to meet any kind of customers' requirement, especially according to International Technology Roadmap for Semiconductors (ITRS) 2003 METROLOGY section1. The process noises resulting from dishing, overlay mark damaging by chemical mechanism polishing (CMP), and the variation of film thickness during deposition are factors which can be very problematic in mark alignment. For example, the conventional "box-in-box" overlay marks could be damaged easily by CMP, because the less local pattern density and wide feature width of the box induce either dishing or asymmetric damages for the measurement targets, which will make the overlay measurement varied and difficult. After Advanced Imaging Metrology (AIM) overlay targets was introduced by KLA-Tencor, studies in the past shown AIM was more robust in overlay metrology than conventional FiF or BiB targets. In this study, the applications of AIM overlay marks under different process conditions will be discussed and compared with the conventional overlay targets. To evaluate the overlay mark performance against process variation on 65nm technology node in 300-mm wafer, three critical layers were chosen in this study. These three layers were Poly, Contact, and Cu-Metal. The overlay targets used for performance comparison were BiB and Non-Segmented AIM (NS AIM) marks. We compared the overlay mark performance on two main areas. The first one was total measurement uncertainty (TMU)3 related items that include Tool Induced Shift (TIS) variability, precision, and matching. The other area is the target robustness against process variations. Based on the present study AIM mark demonstrated an equal or better performance in the TMU related items under our process conditions. However, when non-optimized tungsten CMP was introduced in the tungsten contact process, due to the dense grating line structure design, we found that AIM mark was much more robust than BiB overlay target.
Tseng, H. T.; Lin, Ling-Chieh; Huang, I. H.; Lin, Benjamin S.; Huang, Chin-Chou K.; Huang, Chien-Jen
The Operational Land Imager(OLI) will be the main instrument on Landsat-8 when it launches in 2012. OLI represents a generational change from heritage Landsat instruments in its design but must maintain data continuity with the 30+ year Landsat data archive. As a result, OLI has undergone a stringent calibration and characterization campaign to ensure its characteristics are understood and consistent with past instruments. This paper presents an overview of the OLI design, its major differences from previous Landsat instruments, and a summary of its expected performance.
Markham, Brian L.; Knight, Edward J.; Canova, Brent; Donley, Eric; Kvaran, Geir; Lee, Kenton
Landsat satellites have been operating since 1972, providing a continuous global record of the Earth’s land surface. The imagery is currently available at no cost through the U.S. Geological Survey (USGS). Social scientists at the USGS Fort Collins Science Center conducted an extensive survey in early 2012 to explore who uses Landsat imagery, how they use the imagery, and what the value of the imagery is to them. The survey was sent to all users registered with USGS who had accessed Landsat imagery in the year prior to the survey and over 11,000 current Landsat imagery users responded. The results of the survey revealed that respondents from many sectors use Landsat imagery in myriad project locations and scales, as well as application areas. The value of Landsat imagery to these users was demonstrated by the high importance of and dependence on the imagery, the numerous environmental and societal benefits observed from projects using Landsat imagery, the potential negative impacts on users’ work if Landsat imagery was no longer available, and the substantial aggregated annual economic benefit from the imagery. These results represent only the value of Landsat to users registered with USGS; further research would help to determine what the value of the imagery is to a greater segment of the population, such as downstream users of the imagery and imagery-derived products.
Miller, Holly; Richardson, Leslie A.; Koontz, Stephen R.; Loomis, John; Koontz, Lynne
Information regarding the availability of LANDSAT imagery processed and input to the data files by the NASA Data Processing Facility is published on a monthly basis. The U.S. Standard Catalog includes imagery covering the continental United States, Alaska and Hawaii. the Non-U.S. Standard Catalog identifies all the remaining coverage. Sections 1 and 2 describe the contents and format for the catalogs and associated microfilm. Section 3 provides a cross-reference defining the beginning and ending dates for LANDSAT cycles. Sections 4 and 5 cover LANDSAT-1 and LANDSAT-2 coverage, respectively.
Mapping with Landsat images usually is done by selecting single types of features, such as soils, vegetation, or rocks, and creating visually interpreted or digitally classified maps of each feature. Individual maps can then be overlaid on or combined with other maps to characterize the terrain. Integrated terrain mapping combines several terrain features into each map unit which, in many cases, is more directly related to uses of the land and to methods of land management than the single features alone. Terrain brightness, as measured by the multispectral scanners in Landsat 1 and 2, represents an integration of reflectance from the terrain features within the scanner's instantaneous field of view and is therefore more correlatable with integrated terrain units than with differentiated ones, such as rocks, soils, and vegetation. A test of the feasibilty of the technique of mapping integrated terrain units was conducted in a part of southwestern Queensland, Australia, in cooperation with scientists of the Queensland Department of Primary Industries. The primary purpose was to test the use of digital classification techniques to create a 'land systems map' usable for grazing land management. A recently published map of 'land systems' in the area (made by aerial photograph interpretation and ground surveys), which are integrated terrain units composed of vegetation, soil, topography, and geomorphic features, was used as a basis for comparison with digitally classified Landsat multispectral images. The land systems, in turn, each have a specific grazing capacity for cattle (expressed in beasts per km 2 ) which is estimated following analysis of both research results and property carrying capacities. Landsat images, in computer-compatible tape form, were first contrast-stretched to increase their visual interpretability, and digitally classified by the parallelepiped method into distinct spectral classes to determine their correspondence to the land systems classes and to areally smaller, but readily recognizable, 'land units.' Many land systems appeared as distinct spectral classes or as acceptably homogeneous combinations of several spectral classes. The digitally classified map corresponded to the general geographic patterns of many of the land systems. Statistical correlation of the digitally classified map and the published map was not possible because the published map showed only land systems whereas the digitally classified map showed some land units as well as systems. The general correspondence of spectral classes to the integrated terrain units means that the digital mapping of the units may precede fieldwork and act as a guide to field sampling and detailed terrain unit description as well as measuring of the location, area, and extent of each unit. Extension of the Landsat mapping and classification technique to other arid and semi-arid regions of the world may be feasible.
Robinove, Charles Joseph
Sand dredging has been practiced in rivers, lakes, harbours and coastal areas in recent years in China mostly because of demand from construction industry as building material. Sand dredging has disturbed aquatic ecosystems by affecting hydrological processes, increasing content of suspended sediments and reducing water clarity. Poyang Lake, connecting with Yangtze River in the lower reaches of the Yangtze River, is the largest fresh water lake in China. Sand dredging in Poyang Lake has been intensified since 2001 because such practice was banned in Yangtze River and profitable. In this study, the morphologic change caused by sand dredging in Poyang Lake basin was analysed by overlaying two DEMs acquired in 1952 and 2010 respectively. Since the reflectance of middle infrared band for sand dredging vessel is much higher than that of water surface, sand dredging vessels were showed as isolated grey points and can be counted in the middle infrared band in 12 Landsat images acquired in flooding season during 2000~2010. Another two Landsat images (with low water level before 2000 and after 2010) were used to evaluate the morphologic change by comparing inundation extent and shoreline shape. The following results was obtained: (1) vessels for sand dredging are mainly distributed in the north of Poyang Lake before 2007, but the dredging area was enlarged to the central region and even to Gan River; (2) sand dredging area reached to about 260.4 km2 and is mainly distributed in the north of Songmen Mountain and has been enlarged to central of Poyang Lake from the distribution of sand vessels since 2007. Sand dredged from Poyang Lake was about 1.99 × 109 m3 or 2448 Mt assuming sediment bulk density of 1.23 t m-3. It means that the magnitude of sand mining during 2001-2010 is almost ten times of sand depositions in Poyang Lake during 1955-2010; (3) Sand dredging in Poyang Lake has alternated the lake capacity and discharge section area, some of the watercourse in the northern channel was enlarged by more than 1 km when in low lake level. This study is useful to understand the change of hydrological system, especially the drying up trend in Poyang Lake in recent autumns and winters.
Qi, S.; Zhang, X.; Wang, D.; Zhu, J.; Fang, C.
The hydrogenation of alkynes to alkenes over supported metal catalysts is an important industrial process and it has been shown that hydrocarbonaceous overlayers are important in controlling selectivity profiles of metal-catalysed hydrogenation reactions. As a model system, we have selected propyne hydrogenation over a commercial Pd(5%)/Al2O3 catalyst. Inelastic neutron scattering studies show that the C-H stretching mode ranges from 2850 to 3063 cm-1, indicating the mostly aliphatic nature of the overlayer and this is supported by the quantification of the carbon and hydrogen on the surface. There is also a population of strongly hydrogen-bonded hydroxyls, their presence would indicate that the overlayer probably contains some oxygen functionality. There is little evidence for any olefinic or aromatic species. This is distinctly different from the hydrogen-poor overlayers that are deposited on Ni/Al2O3 catalysts during methane reforming.
Lennon, David; Warringham, Robbie; Guidi, Tatiana; Parker, Stewart F.
September, 2004 Thesis Supervisor: Vladimir Vlassov Associate Professor IMIT / KTH #12;Abstract An overlay of the writing of the thesis. I would also like to thanks my parents for make and effort to let me expend
Maguire Jr., Gerald Q.
The initiation and growth of intergranular stress-corrosion cracking (IGSCC) in the heat affected zone (HAZ) of stainless steel reactor piping welds has been a subject of concern to electric utilities for over ten years. This type of crack can be detected with ultrasonic shear waves during normal maintenance periods with a reliability of up to 80%. Often after an inspection indicating cracks, a utility has been allowed to administer a temporary fix to a pipe which is suspected of being cracked. This fix is a weld metal overlay. The repaired pipes often have to be inspected after the overlay has been put on the pipe. The overlay with a complex, elastically anisotropic microstructure, considerably reduces the reliability of the ultrasonic inspection. This paper addresses the problems arising because of the overlay.
Bright field imaging based metrology performance enhancement is essential in the quest to meet lithography process control requirements below 65 nm half pitch. Recent work has shown that, in parallel to the lithographic processes themselves, the metrology tools are able to continue to perform despite the fact that the size of the features under test are often below the classical Rayleigh resolution limit of the optical system. Full electromagnetic simulation is a mandatory tool in the investigation and optimization of advanced metrology tool and metrology target architectures. In this paper we report on imaging simulations of overlay marks. We benchmark different simulation platforms and methods, focusing in particular on the challenges associated with bright-field imaging overlay metrology of marks with feature sizes below the resolution limit. In particular, we study the dependence of overlay mark contrast and information content on overlay mark pitch and feature size.
Kandel, Daniel; Adel, Michael E.; Frommer, Aviv; Levinski, Vladimir; Rapoport, Alexandra; Silver, Richard M.
Interface evaluations of four high-performance concrete overlays cast on top of one type of normal concrete substrate were made by a new direct shear test method. Two different surface preparations such as mechanical abrasion and chemical etching were followed to manufacture 64 overlay–substrate bi-layer specimens. This paper discusses the material properties and fabrication and evaluations of bi-layer specimens. Results show
Indrajit Ray; Julio F. Davalos; Shiwei Luo
Self-aligned double patterning (SADP) lithography is a promising technology which can reduce the overlay and print 2D features for sub-32nm process. Yet, how to decompose a layout to minimize the overlay and perform hot spot detection is still an open problem. In this paper, we present an algorithm that can optimally solve the SADP decomposition problem. For a decomposable layout,
Hongbo Zhang; Yuelin Du; Martin D. F. Wong; Rasit Topaloglu
Structured peer-to-peer (p2p) overlay networks provide a useful substrate for building distributed applications. They assign object keys to overlay nodes and provide a primitive to route a message to the node responsible for a key. Proximit neighbor selection (PNS) can be used to achieve both low delay routes and low bandwidth usage but it introduces high overhead. This paper presents
Miguel Castro; Peter Druschel; Y. Charlie Hu; Antony Rowstron
This paper examines the strain response of typical HMA overlays above jointed PCC slabs prone to bottom-up reflective cracking. The occurrence of reflective cracking under the combined effect of traffic and environmental loading significantly reduces the design life of the HMA overlays and can lead to its premature failure. In this context, viscoelastic material properties combined with cyclic vehicle loadings and pavement temperature distribution were implemented in a series of FE models in order to study the evolution of horizontal tensile and shear strains at the bottom of the HMA overlay. The effect of several design parameters, such as subbase and subgrade moduli, vehicle speed, overlay thickness, and temperature condition, on the horizontal and shear strain response was investigated. Results obtained show that the rate of horizontal and shear strain increase at the bottom of the HMA overlay drop with higher vehicle speed, higher subgrade modulus, and higher subbase modulus. Moreover, the rate of horizontal strain accumulation increases with higher overlay thickness. Although initial strain values were higher at positive pavement temperature distributions, the corresponding rate of strain increase were higher at negative pavement temperatures. Finally, an extrapolation of the strain history curve for various pavement design parameters was used to estimate the number of cycles for bottom-up crack initiation.
Ziad G. Ghauch; Grace G. Abou Jaoude
In this study, weld overlays of Alloy 52M (a nickel-based filler metal) onto CF8 stainless steel (SS) were performed using the gas tungsten arc welding process. Hot cracking in the weld overlays was observed particularly near the interfacial region of the Alloy 52M/CF8 weld overlay. In general, the hot cracks were most likely to occur at the sites with high dilution rates, e.g., at the weld start/end locations of a single pass or in the first and second passes in multi-pass overlays. The region near the weld interface between Alloy 52M and the CF8 SS had a higher hot cracking tendency than the other regions. It was found that the dilution rate and the formation of eutectic-type constituents (i.e., ?/NbC) both played significant roles in the determination of the hot cracking susceptibility of these weld overlays. Nevertheless, hot cracks were entirely eliminated by proper deposition of a SS buffer layer prior to overlaying with Alloy 52M.
Chu, H. A.; Young, M. C.; Chu, H. C.; Tsay, L. W.; Chen, C.
We present an innovating method to measure the overlay by scatterometry using an optical Fourier transform (OFT) based system. In order to measure the overlay of patterned layers ? and ?, one line grating is placed in layer ? and another in layer ?. The two gratings have the same pitch and their lines are parallel. The whole scattering pattern of the double grating structure is then measured at fixed wavelength in a large range of incidence (0 to 80°) and for all the azimuth angles. This measurement is very rapid thanks to the OFT and not sensitive to vibration. The main advantage of OFT compared to standard OCD techniques like normal incidence reflectometry or spectroscopic ellipsometry is that the scattering pattern is more sensitive to overlay at an azimuth depending on the pitch value which is never parallel or perpendicular to the grooves of the gratings. In addition, the optical response is also sensitive to the sign of the overlay in addition to its amplitude. In a second method, we propose to measure the overlay simultaneously along the two directions of the plane using two bi-periodic structures patterned in layer ? and ?. By using OFT it is possible to deduce directly from the whole diffracted pattern, the overlay signs and amplitudes along both directions of the plane. The paper presents some simulations and some experimental results to illustrate this new method.
Petit, J.; Boher, P.; Leroux, T.; Barritault, P.; Hazart, J.; Chaton, P.
Restrained drying shrinkage cracking was investigated on composite beams consisting of substrate concrete and bonded mortar overlays, and compared to the performance of the same mortars when subjected to the ring test. Stress development and cracking in the composite specimens were analytically modeled and predicted based on the measurement of relevant time-dependent material properties such as drying shrinkage, elastic modulus, tensile relaxation and tensile strength. Overlay cracking in the composite beams could be very well predicted with the analytical model. The ring test provided a useful qualitative comparison of the cracking performance of the mortars. The duration of curing was found to only have a minor influence on crack development. This was ascribed to the fact that prolonged curing has a beneficial effect on tensile strength at the onset of stress development, but is in the same time not beneficial to the values of tensile relaxation and elastic modulus. -- Highlights: •Parameter study on material characteristics influencing overlay cracking. •Analytical model gives good quantitative indication of overlay cracking. •Ring test presents good qualitative indication of overlay cracking. •Curing duration has little effect on overlay cracking.
Beushausen, Hans, E-mail: firstname.lastname@example.org; Chilwesa, Masuzyo