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• 151. [Article] 6 students, 6 iPads, 60 photographs: A qualitative study of undergraduate information practices in the mobile landscape

  Online Northwest, Corvallis, Oregon.February 10,2012

  Citation × Citation Citation Abstract Copy Title: 6 students, 6 iPads, 60 photographs: A qualitative study of undergraduate information practices in the mobile landscape Author: Mellinger, Margaret, Deitering, Anne-Marie Online Northwest, Corvallis, Oregon.February 10,2012 Title: 6 students, 6 iPads, 60 photographs: A qualitative study of undergraduate information practices in the mobile landscape Author: Mellinger, Margaret, Deitering, Anne-Marie Online Northwest, Corvallis, Oregon.February 10,2012 Close

• 152. [Article] Long-term individual sighting history database: an effective tool to monitor satellite tag effects on cetaceans

  This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Inter Research. The published article can be found at: http://www.int-res.com/journals/esr/esr-...

  Citation × Citation Citation Abstract Copy Title: Long-term individual sighting history database: an effective tool to monitor satellite tag effects on cetaceans Author: Gendron, D., de la Cruz, A. Ugalde, Serrano, I. Martinez, Calambokidis, J., Mate, B. This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Inter Research. The published article can be found at: http://www.int-res.com/journals/esr/esr-home/ Title: Long-term individual sighting history database: an effective tool to monitor satellite tag effects on cetaceans Author: Gendron, D., de la Cruz, A. Ugalde, Serrano, I. Martinez, Calambokidis, J., Mate, B. This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Inter Research. The published article can be found at: http://www.int-res.com/journals/esr/esr-home/ Close

• 153. [Article] Western Juniper (Juniperus occidentalis) and invasive annual grass mapping in Eastern Oregon

  In 2011, the Institute for Natural Resources – Portland (INR) entered into an agreement with the Natural Resources Conservation Service through the Cooperative Ecosystem Study Unit to assist in evaluation ...

  Citation × Citation Citation Abstract Copy Title: Western Juniper (Juniperus occidentalis) and invasive annual grass mapping in Eastern Oregon Author: Nielsen, Eric, Noone, Matthew, Kagan, James S. In 2011, the Institute for Natural Resources – Portland (INR) entered into an agreement with the Natural Resources Conservation Service through the Cooperative Ecosystem Study Unit to assist in evaluation of a targeted watershed restoration area in central Oregon. The primary objective of the agreement was to use remote sensing methodologies and widely available data sets to establish baseline landscape conditions that could be utilized by land managers as a planning tool and a measure of restoration project treatment success. Products and analysis developed by INR included: 1) A juniper percent canopy cover map for about 20 million acres in eastern Oregon and a juniper canopy cover increase/decrease map for a 17-year time interval between 1994 and 2011; 2) An exploratory analysis examining the feasibility of utilizing historic aerial photos to map historic juniper conditions; 3) A paired watershed analysis in Wheeler county examining outcomes of recent management activities; and 4) An exotic invasive annual map for 4.3 million acres spanning selected weed prioritization areas. The project was focused on using innovative remote sensing methods to identify the areas with existing juniper and invasive species concentrations. The resulting maps were intended to provide land managers with a preliminary planning tool describing existing baseline conditions across the region to help evaluate the effectiveness of different restoration treatments and identify priority areas for treatments. Title: Western Juniper (Juniperus occidentalis) and invasive annual grass mapping in Eastern Oregon Author: Nielsen, Eric, Noone, Matthew, Kagan, James S. In 2011, the Institute for Natural Resources – Portland (INR) entered into an agreement with the Natural Resources Conservation Service through the Cooperative Ecosystem Study Unit to assist in evaluation of a targeted watershed restoration area in central Oregon. The primary objective of the agreement was to use remote sensing methodologies and widely available data sets to establish baseline landscape conditions that could be utilized by land managers as a planning tool and a measure of restoration project treatment success. Products and analysis developed by INR included: 1) A juniper percent canopy cover map for about 20 million acres in eastern Oregon and a juniper canopy cover increase/decrease map for a 17-year time interval between 1994 and 2011; 2) An exploratory analysis examining the feasibility of utilizing historic aerial photos to map historic juniper conditions; 3) A paired watershed analysis in Wheeler county examining outcomes of recent management activities; and 4) An exotic invasive annual map for 4.3 million acres spanning selected weed prioritization areas. The project was focused on using innovative remote sensing methods to identify the areas with existing juniper and invasive species concentrations. The resulting maps were intended to provide land managers with a preliminary planning tool describing existing baseline conditions across the region to help evaluate the effectiveness of different restoration treatments and identify priority areas for treatments. Close

• 154. [Article] Geology of the Seal Rock Area

  Twelve years ago I was new to the Oregon coast and eager to learn about the natural setting. Field guides were available to birds, marine mammals, tide pools, seaweeds, and forest plants. Not so geology. ...

  Citation × Citation Citation Abstract Copy Title: Geology of the Seal Rock Area Author: Centala, Maxine Twelve years ago I was new to the Oregon coast and eager to learn about the natural setting. Field guides were available to birds, marine mammals, tide pools, seaweeds, and forest plants. Not so geology. I looked at a field guide to rocks and minerals, but it was hard to connect those photos with the basalt and the bluff I saw at the beach. I wished for a nontechnical book about local landforms to tell me about their origin and age. To my knowledge, that volume still doesn’t exist. This work is one layperson’s attempt to fill the void and share what I’ve learned. I discuss how the sedimentary rocks, basalt, marine terraces and sea cliffs in this area were formed and where they are visible. Also included are sections on paleontology and buried forests. Finally, a discussion of earthquakes and tsunamis looks at evidence of past activity in our locality and how these forces may affect the geomorphology of the coast in the future. Marcel Proust once wrote, “The real voyage of discovery consists not in seeking new landscapes but in having new eyes.” Learning local geology has helped me develop a fresh eye to my surroundings and live with greater awareness of the meanings and attachments that connect us to this place, this earth: home. This article is intended for residents and visitors interested in learning more about their surroundings. Geological information can make for dense reading, best absorbed a little at a time. I’ve kept the use of abbreviations and technical language to a minimum. Only four geologic time periods are mentioned frequently: the Oligocene and Miocene for local bedrock and basalt, and the more recent Pleistocene and Holocene for marine terraces and sand dunes. Those who wish to read in greater depth may find the list of references helpful. Since I am not a geologist, I first read popular and scientific works, then communicated with knowledgeable people. Title: Geology of the Seal Rock Area Author: Centala, Maxine Twelve years ago I was new to the Oregon coast and eager to learn about the natural setting. Field guides were available to birds, marine mammals, tide pools, seaweeds, and forest plants. Not so geology. I looked at a field guide to rocks and minerals, but it was hard to connect those photos with the basalt and the bluff I saw at the beach. I wished for a nontechnical book about local landforms to tell me about their origin and age. To my knowledge, that volume still doesn’t exist. This work is one layperson’s attempt to fill the void and share what I’ve learned. I discuss how the sedimentary rocks, basalt, marine terraces and sea cliffs in this area were formed and where they are visible. Also included are sections on paleontology and buried forests. Finally, a discussion of earthquakes and tsunamis looks at evidence of past activity in our locality and how these forces may affect the geomorphology of the coast in the future. Marcel Proust once wrote, “The real voyage of discovery consists not in seeking new landscapes but in having new eyes.” Learning local geology has helped me develop a fresh eye to my surroundings and live with greater awareness of the meanings and attachments that connect us to this place, this earth: home. This article is intended for residents and visitors interested in learning more about their surroundings. Geological information can make for dense reading, best absorbed a little at a time. I’ve kept the use of abbreviations and technical language to a minimum. Only four geologic time periods are mentioned frequently: the Oligocene and Miocene for local bedrock and basalt, and the more recent Pleistocene and Holocene for marine terraces and sand dunes. Those who wish to read in greater depth may find the list of references helpful. Since I am not a geologist, I first read popular and scientific works, then communicated with knowledgeable people. Close

• 155. [Article] Drawing, photography and digital imaging : a comparative study in rock art recording methodology

  Prehistoric rock art has intrigued and fascinated researchers from around the world for nearly 300 years. Having once been embraced for its cultural and scientific uniqueness, the study of prehistoric ...

  Citation × Citation Citation Abstract Copy Title: Drawing, photography and digital imaging : a comparative study in rock art recording methodology Author: Curtis, Gary A. Prehistoric rock art has intrigued and fascinated researchers from around the world for nearly 300 years. Having once been embraced for its cultural and scientific uniqueness, the study of prehistoric rock art showed promise in being able to open new doors of understanding, above and beyond the written record. In time, however, as archaeological interests gradually shifted towards large scale stratigraphic excavation and chronometric dating of artifact assemblages, the enthusiasm and promise of rock art studies were soon forgotten. Unfortunately, the gradual marginalization of rock art research in academic and professional circles has had a deleterious affect on the disciplines theoretical and scientific growth. Methods of documenting rock art have changed little in over 250 years and still involve techniques of recording that are not only invasive and inaccurate, but time and labor intensive. If rock art sites are to be effectively documented for management, conservation and scientific research prior to their destruction, then a fundamental shift in our thinking about bow we approach and record rock art sites is in order. This thesis proposes a change to traditional rock art recording methods in which drawings are the status quo. In a comparative study, this thesis demonstrates that when a more judicious use of drawings is adopted in favor of photography and digital imaging, the recording process becomes more efficient and the data gathered is more accurate and less subjective. In addition, this thesis will demonstrate how photo-editing and digital imaging techniques provide and facilitate the seamless integration of photographic data into the report writing process, and provide new ways in which to view and analyze photographic data scientifically. Title: Drawing, photography and digital imaging : a comparative study in rock art recording methodology Author: Curtis, Gary A. Prehistoric rock art has intrigued and fascinated researchers from around the world for nearly 300 years. Having once been embraced for its cultural and scientific uniqueness, the study of prehistoric rock art showed promise in being able to open new doors of understanding, above and beyond the written record. In time, however, as archaeological interests gradually shifted towards large scale stratigraphic excavation and chronometric dating of artifact assemblages, the enthusiasm and promise of rock art studies were soon forgotten. Unfortunately, the gradual marginalization of rock art research in academic and professional circles has had a deleterious affect on the disciplines theoretical and scientific growth. Methods of documenting rock art have changed little in over 250 years and still involve techniques of recording that are not only invasive and inaccurate, but time and labor intensive. If rock art sites are to be effectively documented for management, conservation and scientific research prior to their destruction, then a fundamental shift in our thinking about bow we approach and record rock art sites is in order. This thesis proposes a change to traditional rock art recording methods in which drawings are the status quo. In a comparative study, this thesis demonstrates that when a more judicious use of drawings is adopted in favor of photography and digital imaging, the recording process becomes more efficient and the data gathered is more accurate and less subjective. In addition, this thesis will demonstrate how photo-editing and digital imaging techniques provide and facilitate the seamless integration of photographic data into the report writing process, and provide new ways in which to view and analyze photographic data scientifically. Close

• 156. [Article] Shoreline erosion on Sauvie Island, Oregon: perceptions and management practices

  Sauvie Island lies at the confluence of the Columbia River and the Willamette River near Portland, Oregon. Flooding, erosion, and deposition of sediments have been part of the natural evolution of the ...

  Citation × Citation Citation Abstract Copy Title: Shoreline erosion on Sauvie Island, Oregon: perceptions and management practices Author: Long, Season Sauvie Island lies at the confluence of the Columbia River and the Willamette River near Portland, Oregon. Flooding, erosion, and deposition of sediments have been part of the natural evolution of the island. However, with the construction of multiple dams in the Columbia River Basin, levees, and hardening of upstream banks, many natural river processes have been altered, resulting in increased erosion along the Island's shores. The objectives of this project were to, (i) characterize shoreline erosion as perceived by waterfront landowners on Sauvie Island, (ii) determine the role of government agencies in shoreline erosion management, (iii) to "ground truth" property owner and agency perceptions of recent erosion problems, and (iv) to communicate project findings to all parties. The research involved surveying shoreline property owners, interviewing relevant government agency staff to determine their roles and responsibilities for erosion management, and the use of aerial and orthophotos to verify erosion "hot spots". The main findings of this study were that: 1) Columbia River residents are the most concerned about bank erosion, with nearly 25 percent of the respondents losing bank along the entire length of their property; 2) nearly half of the Columbia River respondents have installed some form of bank protection along their waterfront, however, only 25 percent believe that their revetment strategy has prevented further erosion; 3) aerial photo analysis revealed section of the Columbia River shoreline having (accumulative) erosion of up to 5 feet per year; 4) current regulatory jurisdiction for erosion monitoring and control along Sauvie Island is disjointed with no single agency responsible for the monitoring, permitting, and technical assistance landowner's need when installing revetment work. An intended outcome of this project is to encourage cooperative management of shoreline erosion by building understanding of the nature of shoreline erosion on Sauvie Island and to facilitate communication between landowners and government agencies regarding extent, management and mitigation. Title: Shoreline erosion on Sauvie Island, Oregon: perceptions and management practices Author: Long, Season Sauvie Island lies at the confluence of the Columbia River and the Willamette River near Portland, Oregon. Flooding, erosion, and deposition of sediments have been part of the natural evolution of the island. However, with the construction of multiple dams in the Columbia River Basin, levees, and hardening of upstream banks, many natural river processes have been altered, resulting in increased erosion along the Island's shores. The objectives of this project were to, (i) characterize shoreline erosion as perceived by waterfront landowners on Sauvie Island, (ii) determine the role of government agencies in shoreline erosion management, (iii) to "ground truth" property owner and agency perceptions of recent erosion problems, and (iv) to communicate project findings to all parties. The research involved surveying shoreline property owners, interviewing relevant government agency staff to determine their roles and responsibilities for erosion management, and the use of aerial and orthophotos to verify erosion "hot spots". The main findings of this study were that: 1) Columbia River residents are the most concerned about bank erosion, with nearly 25 percent of the respondents losing bank along the entire length of their property; 2) nearly half of the Columbia River respondents have installed some form of bank protection along their waterfront, however, only 25 percent believe that their revetment strategy has prevented further erosion; 3) aerial photo analysis revealed section of the Columbia River shoreline having (accumulative) erosion of up to 5 feet per year; 4) current regulatory jurisdiction for erosion monitoring and control along Sauvie Island is disjointed with no single agency responsible for the monitoring, permitting, and technical assistance landowner's need when installing revetment work. An intended outcome of this project is to encourage cooperative management of shoreline erosion by building understanding of the nature of shoreline erosion on Sauvie Island and to facilitate communication between landowners and government agencies regarding extent, management and mitigation. Close

• 157. [Article] Field checking the National Wetlands Inventory at South Slough, Oregon

  The U.S. Fish and Wildlife Service's National Wetlands Inventory (NWI) was developed to map U.S. wetlands comprehensively, following the Cowardin classification system. Wetlands are mapped by the NWI using ...

  Citation × Citation Citation Abstract Copy Title: Field checking the National Wetlands Inventory at South Slough, Oregon Author: Graves, Jonathan K. Year: 1991 The U.S. Fish and Wildlife Service's National Wetlands Inventory (NWI) was developed to map U.S. wetlands comprehensively, following the Cowardin classification system. Wetlands are mapped by the NWI using small scale aerial photographs, but the inventory is not field checked in detail. The accuracy of this inventory has been questioned. During the summer of 1990, I field checked the portion of the NWI map of Charleston, OR Quadrangle containing the South Slough National Estuarine Research Reserve. Using the Cowardin classification, I delineated fresh and saltwater wetlands in the South Slough Reserve and identified wetland plant communities as Cowardin wetland types by field reconnaissance methods. I hypothesized that the NWI would have two kinds of errors: classification errors and delineation errors. A classification error occurs when the Cowardin wetland type is incorrectly designated on the NWI map. A delineation error occurs when the wetland is incorrectly placed on the NWI map, omitted, or included when it was not a wetland. Of the 402.3 ha of wetlands I field checked, 52.4 ha were classified incorrectly and 16.2 ha were delineated incorrectly. On an area-basis the NWI is about 83% accurate in this test case. Given the small scale of air photo interpretation, I judged the NWI to be quite accurate in the South Slough area. Title: Field checking the National Wetlands Inventory at South Slough, Oregon Author: Graves, Jonathan K. Year: 1991 The U.S. Fish and Wildlife Service's National Wetlands Inventory (NWI) was developed to map U.S. wetlands comprehensively, following the Cowardin classification system. Wetlands are mapped by the NWI using small scale aerial photographs, but the inventory is not field checked in detail. The accuracy of this inventory has been questioned. During the summer of 1990, I field checked the portion of the NWI map of Charleston, OR Quadrangle containing the South Slough National Estuarine Research Reserve. Using the Cowardin classification, I delineated fresh and saltwater wetlands in the South Slough Reserve and identified wetland plant communities as Cowardin wetland types by field reconnaissance methods. I hypothesized that the NWI would have two kinds of errors: classification errors and delineation errors. A classification error occurs when the Cowardin wetland type is incorrectly designated on the NWI map. A delineation error occurs when the wetland is incorrectly placed on the NWI map, omitted, or included when it was not a wetland. Of the 402.3 ha of wetlands I field checked, 52.4 ha were classified incorrectly and 16.2 ha were delineated incorrectly. On an area-basis the NWI is about 83% accurate in this test case. Given the small scale of air photo interpretation, I judged the NWI to be quite accurate in the South Slough area. Close

• 158. [Article] Archaeological investigation and technological analysis of the Quartz Mountain Obsidian Quarry, central Oregon

  The Quartz Mountain Obsidian Quarry is located in the Southeast corner of the Bend Fort Rock Ranger District in central Oregon, approximately forty-five miles southeast of Bend, Oregon. The research of ...

  Citation × Citation Citation Abstract Copy Title: Archaeological investigation and technological analysis of the Quartz Mountain Obsidian Quarry, central Oregon Author: Hatch, John B. The Quartz Mountain Obsidian Quarry is located in the Southeast corner of the Bend Fort Rock Ranger District in central Oregon, approximately forty-five miles southeast of Bend, Oregon. The research of the Quartz Mountain Obsidian Quarry began with a literature search of other quarry sites in the area and the use of aerial photos to determine the survey area. After the survey area was established a ground survey was conducted. Following the survey several key areas were chosen for surface collections that could answer key questions: What types of core reductions were being used on Quartz Mountain?; and What types of materials were being utilized? (red/black obsidian found in rhyolite veins, red/black obsidian found in fist sized and larger nodule form, or large block black obsidian). In order to answer these questions three collection units were established. The lithic material from the units was collected and analyzed and the information placed into a database, which was then grouped for statistical analysis, and generated into charts and tables. The resulting data was then compared to the information found from an extensive literature search to see how the material that I collected compared to those found at other quarry sites. From this information I was able to determine that two different core reduction methods were being used on Quartz Mountain: blade core and bifacial core. Along with the different core reduction methods a mobility strategy also came into play. In this thesis I will use the data gathered to determine the different core reduction methods and the mobility strategies that are associated with them. Title: Archaeological investigation and technological analysis of the Quartz Mountain Obsidian Quarry, central Oregon Author: Hatch, John B. The Quartz Mountain Obsidian Quarry is located in the Southeast corner of the Bend Fort Rock Ranger District in central Oregon, approximately forty-five miles southeast of Bend, Oregon. The research of the Quartz Mountain Obsidian Quarry began with a literature search of other quarry sites in the area and the use of aerial photos to determine the survey area. After the survey area was established a ground survey was conducted. Following the survey several key areas were chosen for surface collections that could answer key questions: What types of core reductions were being used on Quartz Mountain?; and What types of materials were being utilized? (red/black obsidian found in rhyolite veins, red/black obsidian found in fist sized and larger nodule form, or large block black obsidian). In order to answer these questions three collection units were established. The lithic material from the units was collected and analyzed and the information placed into a database, which was then grouped for statistical analysis, and generated into charts and tables. The resulting data was then compared to the information found from an extensive literature search to see how the material that I collected compared to those found at other quarry sites. From this information I was able to determine that two different core reduction methods were being used on Quartz Mountain: blade core and bifacial core. Along with the different core reduction methods a mobility strategy also came into play. In this thesis I will use the data gathered to determine the different core reduction methods and the mobility strategies that are associated with them. Close

• 159. [Article] Annotation of image segments with ontologies (AISO)

  This M.S thesis presents an interactive software tool that I have developed in the course of the past two years. This interactive tool is called AISO. AISO is aimed at interactive image segmentation and ...

  Citation × Citation Citation Abstract Copy Title: Annotation of image segments with ontologies (AISO) Author: Lingutla Venkata, Nikhil Tej This M.S thesis presents an interactive software tool that I have developed in the course of the past two years. This interactive tool is called AISO. AISO is aimed at interactive image segmentation and annotation tool designed to allow users to segment an image – such as those produced with digital photography or from scanned prints – and then annotate those segments with ontology terms. Many photo-editing and illustration soft- ware packages enable the ad-hoc editing of an image, but any highlighting and labeling utility requires thorough knowledge of the softwares illustration capabilities (i.e. lay- ering, boundary detection) and does not include the structured integration of scientific data. For example, any labels applied to hand-illustrated segments super-imposed onto an image would have to be individually constructed and associated with a particular portion of an image. AISO simplifies this functionality and requires only a few input gestures and clicks to identify and label segments. The resulting structured image and ontology data allows for consistent extraction techniques. Researchers are thus empow- ered to construct meaningful image data sets drawn from their laboratories, online image archives, and publications. For this thesis I evaluated AISO by soliciting feedback from a selected group of biological researchers. They provided overall positive feedback on user friendliness, consistency and predictability of AISO, speed of interaction of AISO. As the key contribution, this thesis provides the first open source software for plant biologists by integrating the state-of-the-art image segmentation algorithms with plant ontology webservice. Based on our preliminary user study, AISO has potential to significantly advance current practices in plant biology research. Title: Annotation of image segments with ontologies (AISO) Author: Lingutla Venkata, Nikhil Tej This M.S thesis presents an interactive software tool that I have developed in the course of the past two years. This interactive tool is called AISO. AISO is aimed at interactive image segmentation and annotation tool designed to allow users to segment an image – such as those produced with digital photography or from scanned prints – and then annotate those segments with ontology terms. Many photo-editing and illustration soft- ware packages enable the ad-hoc editing of an image, but any highlighting and labeling utility requires thorough knowledge of the softwares illustration capabilities (i.e. lay- ering, boundary detection) and does not include the structured integration of scientific data. For example, any labels applied to hand-illustrated segments super-imposed onto an image would have to be individually constructed and associated with a particular portion of an image. AISO simplifies this functionality and requires only a few input gestures and clicks to identify and label segments. The resulting structured image and ontology data allows for consistent extraction techniques. Researchers are thus empow- ered to construct meaningful image data sets drawn from their laboratories, online image archives, and publications. For this thesis I evaluated AISO by soliciting feedback from a selected group of biological researchers. They provided overall positive feedback on user friendliness, consistency and predictability of AISO, speed of interaction of AISO. As the key contribution, this thesis provides the first open source software for plant biologists by integrating the state-of-the-art image segmentation algorithms with plant ontology webservice. Based on our preliminary user study, AISO has potential to significantly advance current practices in plant biology research. Close

• 160. [Article] Electrical and optical properties of semi-insulating and ion-implanted GaAs and InP

  The electrical and optical properties of semi-insulating, epitaxial and ion-implanted GaAs and InP have been characterized and analyzed. Electron and hole traps in semi-insulating GaAs and InP, with activation ...

  Citation × Citation Citation Abstract Copy Title: Electrical and optical properties of semi-insulating and ion-implanted GaAs and InP Author: Rhee, Jin Koo The electrical and optical properties of semi-insulating, epitaxial and ion-implanted GaAs and InP have been characterized and analyzed. Electron and hole traps in semi-insulating GaAs and InP, with activation energies ΔE[subscript T] ranging from 0.16 ± 0.01 to 0.98 ± 0.01 eV, have been detected and characterized by Photo-Induced Current Transient measurements. The thermal capture cross section and density of the traps have been estimated and some of the centers have been related to native defects. In particular, the activation energy of the compensating Cr, Fe and "0" levels in semi-insulating GaAs and InP were accurately measured. The transient measurements were complemented by Hall measurements at T > 300K and photocurrent spectra measurements. The transition energies for the deep compensating levels obtained by the analyses of data from these measurements, when compared with those from the transient measurements, indicate negligible lattice-coupling of these centers. Analysis of the transport data also indicates that neutral impurity scattering plays a significant role in semi-insulating materials at high temperatures. Semi-insulating GaAs and InP, vapor phase epitaxial GaAs, and liquid phase epitaxial InP were implanted with ²⁸Si⁺ to evaluate the changes in transport properties and deep-level spectra. The dominant 0.83 eV electron trap in VPE GaAs and 0.38 eV electron trap and 0.22 eV hole trap in LPE InP were removed and new traps were created. Electron traps with ΔE[subscript T] = 0.52 ± 0.01 eV and hole traps with ΔE[subscript T] = 0.15 ± 0.01 eV were consistently detected in implanted and annealed GaAs, irrespective of the type of starting material. These centers are characteristic of the implant and anneal processing in GaAs. Similarly, an electron trap with ΔE[subscript T] = 0.17 ± 0.01 eV was consistently detected in implanted LPE InP. A significant reduction in electron mobility for T < 300K was observed in epitaxial GaAs and InP after implant and anneal. The mobility data were analyzed in detail and it is apparent that the reduction in mobility is due to increased impurity scattering and not due to implant damage. Title: Electrical and optical properties of semi-insulating and ion-implanted GaAs and InP Author: Rhee, Jin Koo The electrical and optical properties of semi-insulating, epitaxial and ion-implanted GaAs and InP have been characterized and analyzed. Electron and hole traps in semi-insulating GaAs and InP, with activation energies ΔE[subscript T] ranging from 0.16 ± 0.01 to 0.98 ± 0.01 eV, have been detected and characterized by Photo-Induced Current Transient measurements. The thermal capture cross section and density of the traps have been estimated and some of the centers have been related to native defects. In particular, the activation energy of the compensating Cr, Fe and "0" levels in semi-insulating GaAs and InP were accurately measured. The transient measurements were complemented by Hall measurements at T > 300K and photocurrent spectra measurements. The transition energies for the deep compensating levels obtained by the analyses of data from these measurements, when compared with those from the transient measurements, indicate negligible lattice-coupling of these centers. Analysis of the transport data also indicates that neutral impurity scattering plays a significant role in semi-insulating materials at high temperatures. Semi-insulating GaAs and InP, vapor phase epitaxial GaAs, and liquid phase epitaxial InP were implanted with ²⁸Si⁺ to evaluate the changes in transport properties and deep-level spectra. The dominant 0.83 eV electron trap in VPE GaAs and 0.38 eV electron trap and 0.22 eV hole trap in LPE InP were removed and new traps were created. Electron traps with ΔE[subscript T] = 0.52 ± 0.01 eV and hole traps with ΔE[subscript T] = 0.15 ± 0.01 eV were consistently detected in implanted and annealed GaAs, irrespective of the type of starting material. These centers are characteristic of the implant and anneal processing in GaAs. Similarly, an electron trap with ΔE[subscript T] = 0.17 ± 0.01 eV was consistently detected in implanted LPE InP. A significant reduction in electron mobility for T < 300K was observed in epitaxial GaAs and InP after implant and anneal. The mobility data were analyzed in detail and it is apparent that the reduction in mobility is due to increased impurity scattering and not due to implant damage. Close