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The possibility of using synthetic aperture sonar (SAS) processing techniques on a multibeam volume imaging sonar (the Buried Object Search Sonar, or BOSS) is explored. A system algorithm is developed which involves first forming several parallel synthetic apertures from a translated array oriented in the cross‐track direction, then beamforming the synthetic apertures to form a fully 3D volumetric representation. The validity of the technique is verified by taking data from a subaperture of an experimental cable‐guided multibeam system and applying the SAS processing string. Test targets are examined, including spheres and cylinders. The process proved quite robust, particularly considering that the system was not originally designed for SAS processing, and no sophisticated motion compensation schemes were employed. Implications for multibeam SAS processing of future AUV‐based systems are discussed. [Work supported by ONR’s National Research Enterprise Internship Program, and performed at Naval Surface Warfare Center, Panama City, FL.]

A recent transmission loss experiment was conducted in Long Beach Harbor for the THUMS Long Beach Company. The objective of the experiment was to measure the range at which the received level was 160 dB for compliance with Marine Mammal regulations. This short experiment provided the opportunity to test the rapid geo‐acoustic characterization (RGC) algorithm and perform real‐time geo‐acoustic inversions from a seismic source. The airgun source transmitted pulses every 20 s corresponding to every 45 m. The water depth was 10–15 m and the water was assumed to be iso‐velocity. The data quality was excellent, providing clear striation patterns in the broadband frequency display. The RGC algorithm matches the observed time‐spread, striation slope, and TL slope to precomputed values using a normal mode algorithm and parametric geo‐acoustic profiles based on Hamilton and Bachman’s model. Precomputation of the acoustic observables, combined with real‐time signal processing permits real time geo‐acoustic characterization.

PURPOSE: We conducted a phase I and pharmacologic study of a weekly 96-hour infusion of irinotecan to determine the maximum-tolerated dose, define the toxicity profile, and characterize the clinical pharmacology of irinotecan and its metabolites. PATIENTS AND METHODS: In 26 adult patients with solid tumors, the duration and dose rate of infusion were escalated in new patients until toxicity was observed. RESULTS: In 11 patients who were treated with irinotecan at 12.5 mg/m2/d for 4 days weekly for 2 of 3 weeks, dose-limiting grade 3 diarrhea occurred in three patients and grade 3 thrombocytopenia occurred in two patients. The recommended phase II dose is 10 mg/m2/d for 4 days given weekly for 2 of 3 weeks. At this dose, the steady-state plasma concentration (Css) of total SN-38 (the active metabolite of irinotecan) was 6.42 ± 1.10 nmol/L, and the Css of total irinotecan was 28.60 ± 17.78 nmol/L. No patient experienced grade 3 or 4 neutropenia during any cycle. All other toxicities were mild to moderate. The systemic exposure to SN-38 relative to irinotecan was greater than anticipated, with a molar ratio of the area under the concentration curve (AUC) of SN-38 to irinotecan of 0.24 ± 0.08. One objective response lasting 12 months in duration was observed in a patient with metastatic colon cancer. CONCLUSION: The recommended phase II dose of irinotecan of 10 mg/m2/d for 4 days weekly for 2 of 3 weeks was extremely well tolerated. Further efficacy testing of this pharmacologic strategy of administering intermittent low doses of irinotecan is warranted.

Controlling wildfires within the wildland/urban interface has proven to be the most complex challenge facing wildland fire agencies. Although program improvements to increase the efficiency of interface suppression efforts have been suggested, the availability of information about the wildfire environment remains a critical resource for wildland fire planning. Geographic Information Systems (GISs) can provide the technology to store, manipulate, analyze, and display spatially oriented information in a form necessary for efficient fire planning and incident decision making. Complex map and attribute information, including vegetation types, fuels models, weather patterns, topography, fire suppression environment, landuse characteristics, and microenvironmental features, can be rapidly summarized and integrated. This integrated information can be used to create unique polygons useful in predicting fire behavior, allocating fire suppression resources, and as an aid in planning land use. Simplified user interfaces and the portability of new hardware systems will allow GISs to be used at every level of wildland fire planning.

Includes bibliographical references., The thesis describes the development of a specification for, and prototypes of, an opto-electric voice communications link. The introductory sections deal with the generalised optical communications channel, the available hardware, and some of the research that has been done in the field. The information presented is used to motivate the type of system to be developed. The emphasis is placed on cost, though not as an overriding consideration. Modulation systems are examined, and frequency modulation of an m.f. subcarrier is chosen. The development of the practical system is covered in detail, in particular the receiver frontend circuitry. Considerable discrepancies between the design figures and actual measured performance are analysed, and their causes located. A practical mechanical design is presented, with suggested modifications for production. In conclusion, future developments in the field are examined.

At GWU, we have rejected the notion that Systems Programmers can not deal with people, and we have kept the consulting function as part of systems' responsibility. In addition, we have maintained a consultant policy that we do not 'do' for users; we attempt to educate, to guide, and to teach, so that our users can eventually 'do' for themselves.To aid our staff in meeting these objectives, we developed, in conjunction with the University Counseling Center, a structured workshop to teach programmers human-relation skills. This program has been successful over the past three years, because we have found that intelligent, technically oriented people respond well, when presented with consulting methods in a technical fashion.

The goal of this integrated and cross-campus project is to sense the environment from the leaf to the landscape level. Aspects of the project include, but are not limited to: (1) NIMS and fixed-camera technologies that allow the real-time and automated observation of plant phenological events: leaf flushes, flowering, herbivore attack, and pollination and flower-visitation events. (2) Embedded micro-sensors that include light sensors sensitive to photosynthetic photon flux (PPF; 400-700 nm wavelength) installed on leaf surfaces indicate leaf- and plant-level responses to changes in light conditions, sap flow sensors that measure the velocity at which the transpiration stream flows by the dissipation of heat within a branch, and micrometeorological sensors that monitor conditions that change the driving force for transpiration and affect water balance on a plant- and landscape-level. (3) Minirhizotron tubes enable the direct measurement of root growth and allow for the estimations of microbial activity in the soil.