skip to content


Works: 51 works in 55 publications in 1 language and 55 library holdings
Publication Timeline
Exploiting stochasticity in systematic search : results on a highly structured domain by Carla Gomes( Book )
2 editions published in 1997 in English and held by 1 library worldwide
We introduce a new benchmark domain for hard computational problems that bridges the gap between purely random instances and highly structured problems. We show how to obtain interesting search problems by introducing random perturbations into a structured domain, and how such problems can be used to study the robustness of search control mechanisms. Our experiments demonstrate that the performance of search strategies designed to mimic direct constructive methods degrade surprisingly quickly in the presence of even minor perturbations. On the other hand, our experiments show that by adding a random element to a complete search procedure we can dramatically improve the performance of deterministic methods. These results apply both for the case of finding consistent models as well as for the case of proving inconsistency, complementing the well known success of using randomness in incomplete model find procedures. We pushed the idea of exploiting stochasticity one step further by combining algorithms that exhibit competing behavior into portfolios. Our results show that a portfolio approach can have a dramatic impact in terms of the overall performance, in comparison to the performance of each of its component algorithms. An interesting special case is when the best strategy consists of combining copies of the same algorithm. This portfolio is analogous to the practice of 'restarts' for stochastic procedures, where the same algorithm is run repeatedly with different seeds, a common practice in the theorem proving community. Combining copies of the same algorithm into a portfolio might be a good strategy, especially in the cases that one algorithm dominates for a given class of problems
Macromodeling Electromagnetic Effects in Circuits by Daniel J Kenneally( Book )
2 editions published in 1997 in English and held by 1 library worldwide
This report presents results of an investigation to develop CAD macromodels for simulating and assessing electromagnetic (EM) effects in linear and digital ICs. The effects of interest are any unintended IC responses due to inadvertently (or intentionally) coupled EM energy entering into any accessible ports on the victim circuit. Assessments of possible EM effects require robust methodology to encompass a variety of coupling waveforms and conditions. In this study, both Thevenin and Norton sources were used as equivalent circuits for coupling the intrusive EM fields. Both digital and linear ICs were used as victim circuits to determine and benchmark performance of the candidate macros. Three ICs of representative families, however, were specifically selected for bench marking because they are used in current and planned Air Force Systems. In addition, other contemporary linear ICs and OpAmp's were used in various circuit configurations to demonstrate use of the (EM) assessment macromodels
Experimental Studies of Laminar, Transitional, and Turbulent Hypersonic Flows Over Elliptic Cones at Angles of Attack ( Book )
2 editions published in 1998 in English and held by 1 library worldwide
An experimental study has been performed to examine the three-dimensional characteristics of laminar, transitional and turbulent flow over an elliptic cone lifting body configuration. The experimental studies were performed at Mach numbers between 8 and 12 at Reynolds numbers, based on model length from 5 x 10(exp 5) to 5 x 10(exp 6). Detailed measurements of the distribution of heating and pressure were made along the leading edges and on the windward and leeward surfaces of the model with over 200 high-frequency, thin-film heat transfer gages and piezoelectric high-frequency pressure transducers. Measurements were also performed using temperature sensitive paints to further delineate the properties of the three-dimensional transitional flow. Schlieren photographs were also obtained of the transitional flow field over the models. Flowfield calibration measurements were made in the LENS facility with intrusive pitot and total heating transducers and nonintrusive electron beam, and infrared radiometer techniques. These data have been incorporated into the CUBRC/AFOSR Hypersonic Database which has been modified to run on the Windows platform
Large Energy National Shock Tunnel (LENS), Description and Capabilities ( Book )
2 editions published in 1990 in English and held by 1 library worldwide
The Calspan University at Buffalo Research Center (CUBRC) Large Energy National Shock Tunnel (LENS) is high enthalpy facility constructed to provide duplication of flight velocities in the range from 6000 to 14,000 ft/sec at typical re-entry altitudes, satisfying a requirement for the experimental study of turbulent compressible flows and real gas chemistry in hypervelocity flows. The design of this facility was based on our extensive and successful experience with the 48 and 96 inch shock tunnels at Calspan. These facilities have been used extensively in fundamental research and testing programs in hypersonic flow and include: (1) detailed surface and flowfield measurements in laminar and turbulent regions of shock wave boundary layer interaction for code validation, (2) studies of window cooling with film and transpiration cooling techniques, (3) refraction and dispersion of light by shock waves and turbulent viscous layers, (4) microwave plasma interaction studies, (5) SCRAMJET performance studies including hydrogen air mixing and combustion under flight duplicated conditions in hypersonic flow, and (6) force, moment, pressure, heat transfer and skin friction measurements as well as flowfield surveys on simple and complex hypersonic vehicle configurations
National Center for Multisource Information Fusion ( Book )
1 edition published in 2009 in English and held by 1 library worldwide
The National Center for Multisource Information Fusion (N-CMIF) research was a joint collaboration between CUBRC, University at Buffalo (UB), Rochester Institute of Technology (RIT) and Penn State University (PSU) to address information fusion research gaps present in situation, threat, and impact assessment (JDL levels 2 and 3) as well as sensor management (JDL level 4) and visualization. While much of the research conducted under N-CMIF emphasized computer security, the research also aimed to address the problems in a manner applicable to other domains. Major accomplishments in N-CMIF include (1) addressing current gaps in information fusion and computer security; (2) the enhancement of the Cyber Attack Simulator (a tool to automatically generate cyber attack scenarios for a given computer network); (3) Future Situation and Impact Awareness (FuSIA) (a level 2/3 framework implemented in Java that enhances situation awareness by identifying the current and future impact of a situation as well as providing run-time performance metrics to evaluate the quality of the assessments); (4) two different sensor management techniques for computer networks; (5) semantic and contextual reasoning of cyber attacks; and (6) the visualization of cyber attacks
Lithium Niobate Arithmetic Logic Unit by Andrew R Pleszkun( Book )
1 edition published in 1991 in English and held by 1 library worldwide
Initial development of an optical-serial arithmetic unit is explored. The design is based on lithium-niobate directional-coupler devices as the optical switching elements. The devices can be interconnected by optical fiber to create logic functions with which digital-optic systems may be constructed. Circuit designs for implementing bit-serial multipliers and dividers are presented. Experimental procedures for characterization of lithium-niobate switch performance are described, Measurement of drive-electronics delay is addressed
Strategies for Parallel AI Implementations by William B Day( Book )
1 edition published in 1990 in English and held by 1 library worldwide
This report examines computer architectures that are appropriate for the Parallel Knowledge Based System (PKS). As part of this effort, the PKS (originally simulated in Ada) was rewritten in C and renamed the Distributed Datalog (DDL) interpreter. The DDL runs a network of message passing nodes and is a model for either a multiprocessor executing a DDL program within a distributed memory or a logic program distributed among several nodes. This report describes the DDL architecture, addresses appropriate multiprocessor architectures for the DDL, describes the current DDL implementation and discusses a new memory allocation algorithm for the DDL
Discretionary Security for Object-Oriented Database Systems by Teresa F Lunt( Book )
1 edition published in 1991 in English and held by 1 library worldwide
The discretionary access controls in today's computer systems are designed to enforce a specific access control policy. An application whose access control policies do not easily match the policy that is wired into the system is forced to work around that wired-in policy. As a result, the application itself must enforce discretionary security and cannot make use of the assurances of the computer system's discretionary access controls. This report presents a flexible approach to discretionary access control that allows the implementation of arbitrary access control policies. The generality of the approach allows a user to implement a discretionary access control policy that is tailored to an application, rather than having to work around a specific policy that is wired into the computer system. The report focuses on discretionary controls for object-oriented systems. Object-oriented systems are an emerging technology of great import for applications in business, industry, and the military. Many of these applications must share information among users with different needs and authorizations. The specific access rules desired will vary from application to application. Thus, a flexible approach to discretionary access control for such systems is proposed
Experimental Studies of Shock Interaction Phenomena Associated with Hypersonic Airbreathing Propulsion ( file )
1 edition published in 2001 in English and held by 0 libraries worldwide
Experimental studies were conducted in conjunction with computations in a code validation exercise to examine the ability of DSMC and Navier-Stokes techniques to predict the complex characteristics of regions of shock/shock and shock/boundary layer interactions in hypervelocity flows. In the experimental program, detailed heat transfer and pressure measurements in laminar regions of shock wave/boundary layer interaction, and shock/shock interaction, over hollow cylinder/flare and double cone configurations in hypersonic flow. In the best Navier-Stokes solutions the structure and density of the flowfield was captured exactly over both the hollow cylinder/flare and double cone models. The detailed characteristics of the distribution of pressure and heating through the interaction regions were well predicted. In general, for these relatively high-density flows, the DSMC solutions did not capture the characteristics of well-separated flows. In Part 2 of this program, experimental studies have been conducted in the LENS I shock tunnel to investigate the characteristics and performance of full-scale scramjet engines at fully duplicated flight conditions for a range of dynamic pressures at Mach 7. In this program we obtained detailed heat transfer and pressure measurements together with high speed Schlieren and infrared imagery to determine the characteristics of a generic engine, the flow path of which was configured to be similar to the Air Force Hy-Tech configuration for studies with hydrocarbon and hydrogen fuels
NOPP Aerosol Process Experiments: Phase 2 Data Report ( file )
1 edition published in 1999 in English and held by 0 libraries worldwide
Data obtained by the Calspan-UB Research Center (CUBRC) during the National Oceanographic Participative Program (NOPP) Phase II Aerosol Process Experiments is presented. These experiments were performed in Calspan's 600M3 Atmospheric Research Chamber. CUBRC was responsible for Chamber operations and performance, collaborated with the principal investigators from the Naval Research Laboratory and University of Washington, and with the participating scientists from the National Center for Atmospheric Research, Aerodyne, Environment Canada and the University of Delaware. CUBRC was responsible for the measurement of liquid water content during cloud processing experiments and hydrocarbons (HC's) in experiments designed to study aerosol formation and nucleation in the presence of HC's
Natural Language Processing Systems Evaluation Workshop Held in Berkely, California on 18 June 1991 ( file )
1 edition published in 1991 in English and held by 0 libraries worldwide
The Natural Language Processing Systems Evaluation Workshop provided a forum for computational linguists to discuss current evaluation efforts and activities, research progress, and new approaches; promoted scientific interchange on important evaluation issues; and generated recommendations and directions for future investigations in the evaluation area
Non-Equilibrium Radiation from Shock-Heated Air ( file )
1 edition published in 1991 in English and held by 0 libraries worldwide
A research program is described whose objectives include the quantitative measurement of the ultraviolet radiation behind strong shock waves in air, the identification of the radiating species and the determination of the mechanisms and rates that govern the emission. A shock tube was used to generate 3-4 km/s shock waves through air and oxygen nitrogen mixtures at initial pressures between 0.36-2.25 torr. The temporal gas-radiance profiles recorded radiometrically exhibited strong non-equilibrium overshoots, followed by decay to steady-state equilibrium. The dependence of the peak overshoot values on wave speed and pressure was measured and shown to scale with density. Emission spectra of the gas both in the overshoot region and the equilibrium region showed the NO gamma band system between 210 and 340 nm to be the dominant radiation source. The role of O2 Schumann-Runge radiation in this region was also studied; in pure O2 no overshoot was recorded. Infrared vibronic emission profiles were also measured and shown to be a description of the NO concentration growth. It was found that currently accepted rates for air ground-state chemistry do not predict the NO generation correctly. Finally, a simplified excitation model is suggested to describe the ultraviolet radiation behind the shock wave
Constraints Logic Programming in Knowledge-Based Planning Domains by William B Day( file )
1 edition published in 1992 in English and held by 0 libraries worldwide
This report describes an investigation of constraint logic programming languages and their application to knowledge-based planning systems. An overview of constraint logic programming (CLP) languages is presented with specific attention to CLP(R), a Prolog based CLP language. Two planning/ scheduling systems are presented and features identified as potential sources of CLP(R) improvements. Finally, two examples are presented ... Artificial intelligence, Knowledge-based planning, Logic programming, Constraint logic programming, Constraint satisfaction
Shock Wave/Turbulent Boundary Layer Interaction in High-Reynolds-Number Hypersonic Flows ( file )
1 edition published in 1987 in English and held by 0 libraries worldwide
This report investigated fundamental aerothermal phenomena in hypersonic flow, with particular emphasis on viscous/inviscid interaction phenomena. The experimental studies were conducted to examine the changes in the structure at the base of a hypersonic turbulent boundary layer as it is subjected to a strong self-induced pressure gradient in regions of shock wave/ boundary layer interaction. The initial phase of the theoretical program was directed toward summarizing existing techniques for obtaining Navier/Stokes solutions for laminar flow over flat plates in hypersonic flow. In the experimental program, surface and flow field measurements were made to examine the detailed flow mechanics associated with turbulent boundary layer separation over a large cone flare model at Mach numbers 11, 13 and 16 and Reynolds numbers up to 100 million. Holography measurements were used to examine the flow field regions of hypersonic shock wave/turbulent boundary layer interaction. In this preliminary investigation of the application of holography in a 96 inch Shock Tunnel, holographic interferograms were obtained for viscous/inviscid interactions at Mach numbers 11 and 13 and Reynolds numbers up to 30 million, nominally. Flow field studies were made for flat plate/wedge, cone/flare and incident shock configurations. The quantitative results presented offer new information as well as a potential to obtain density measurements in other types of hypersonic flow; however, they also reveal important concerns which need to be resolved before the interferometric data can be claimed to give accurate measurements of these flows. Two appendices include an invited review paper on aerothermal problems associated with hypersonic flight
Tunable SiGe Detectors ( file )
1 edition published in 1996 in English and held by 0 libraries worldwide
The theory of voltage tunable cut off wavelength silicide/SiGe/Si detectors is presented. Experimental data on tunable PtSi/SiGe/Si detectors is also presented. The theory is able to account for the experimentally observed behavior of tunable PtSi/SiGe/Si diodes. The tunability provided by the SiGe layer is understood as being due to two related effects: first, keeping the barrier peak position fixed with bias; and second, moving the barrier peak further away from the interface. The second effect decreases quantum efficiency, which depends on the peak to interface distance. However, maximizing the first effect allows us to obtain desired levels of tunability without potential decreases in quantum efficiency. For voltage switched, dual window imaging, a tunable range of 5-12 microns is required over moderate voltages (10-15 volts), for which calculated detector parameters are Ge percentages of at least 20%, and total SiGe thicknesses (uniform plus graded) of approx. 60-100 A and boron doping levels of approx. 4-8 x 10 to the 16th cm-3 throughout the depletion layer width (approx. 4000 A, in the SiGe and in the underlying S1)
Automatic scheduling of outages of nuclear power plants with time windows by Carla Gomes( file )
1 edition published in 1996 in English and held by 0 libraries worldwide
This report describes a successful project for transference of advanced AI technology into the domain of planning of outages of nuclear power plants as part of DOD's dual-use program. ROMAN (Rome Lab Outage Manager) is the prototype system that was developed as a result of this project. ROMAN's main innovation compared to the current state-of-the-art of outage management tools is its capability to automatically enforce safety constraints during the planning and scheduling phase. Another innovative aspect of ROMAN is the generation of more robust schedules that are feasible over time windows. In other words, ROMAN generates a family of schedules by assigning time intervals as start times to activities rather than single start times, without affecting the overall duration of the project. ROMAN uses a constraint satisfaction paradigm combining a global search tactic with constraint propagation. The derivation of very specialized representations for the constraints to perform efficient propagation is a key aspect for the generation of very fast schedules - constraints are compiled into the code, which is a novel aspect of our work using an automatic programming system, KIDS
Investigation of Unsteady Flow in an Annular Cascade ( file )
1 edition published in 1991 in English and held by 0 libraries worldwide
The proper orthogonal decomposition (POD) was used to test the hypothesis that there exist a set of functions which characterize a turbine stator exit flowfield and whose dynamics may explain some of the complex behavior in downstream blade rows. The decomposition was applied to three component triple-wire probe measurements of a large-scale annular stator model exit flowfield. This study represents the first application of the orthogonal decomposition to directly measured three component data, and one of the first applications to an applied engineering flow. The full three-component cross- spectral tensor was produced from simultaneous multipoint triple-wire probe measurements. The measurements were taken across one stator pitch, at the passage midspan, 10% axial chord downstream of the stator trailing edge. The resulting 1089 cross-spectral estimates were then decomposed to obtain the eigenspectra and eigenmodes of the midspan flowfield. In addition, the POD was applied to two subdomains of the passage flowfield in order to increase the convergence rate of the energy representation. The two subdomains were taken to be the wake and outer flow region because of the large difference in scales between those regions. The wake spanned approximately 20% of the stator pitch at the measurement plane. Large distinct low frequency peaks (below 200Hz) were found in many of the eigenmodes although not consistently at the same frequencies. These peaks were considered the result of either inlet flow disturbances or migration of passage generated flows structures. More detailed measurements are needed however, to determine the nature of the source of these low frequency (apparently large spatial scale) structures
Experiments in Numerical Studies of Low Density and Real Gas Effects on Regions of Shock Wave/Boundary Layer Interaction in Hypervelocity Flows ( file )
1 edition published in 2006 in English and held by 0 libraries worldwide
Experiments with extensive numerical simulations were conducted examining effects of low density flows and real gas effects on aerothermal characteristics of flows in hypervelocity facilities and in simple and complex flowfields in hypervelocity flows. These studies demonstrated that in the absence of real gas effects the DSMC and Navier-Stokes solutions accounting for slip effects were in excellent agreement with measurements. An extensive series of calibration and validation studies were done defining the free stream flows in the LENS I and X tunnels for low density and high enthalpy flows at velocities up to 16,000 ft/s. Measurements on double cone configuration showed that above 13,000 ft/s the interaction regions differed significantly in nitrogen and air flows; while the computations agreed with the measurements in nitrogen, they differed significantly in the size and properties of interaction regions in air. With the shuttle configuration, we demonstrated that real gas effects decrease the size of a separated interaction region over the flap, reduce the pressure over the adjacent curved surfaces, and reduce Reynolds number for onset of boundary layer transition
A frame work for performance evaluation of multi target tracking systems by Sanjay Rawat( file )
1 edition published in 2002 in English and held by 0 libraries worldwide
This report is a part of research conducted at the Center for Multisource Information Fusion (CMIF) at the State University of New York at Buffalo (SUNY at Buffalo) during the second arid third year of a three-year Air Force Office of Scientific Research (AFOSR)-funded research grant to Calspan-UB Research Center, Inc. (CUBRC). The overarching research objective of this grant is to provide understanding about the nature of multi-platform and distributed data fusion and the influence that such methods might have on flight-testing of future multi-platform systems at major range facilities such as, in particular, Edwards Air Force Base, and also with a special focus on Electronic Warfare (EW) aspects and impacts. The effort stems from the visions for future combat depicted in various DoD forward-looking documents such as Joint Vision 2010 (JV2O 10), the Advanced Battlespace Information System (ABIS), and New World Vistas (NWV), among other similar reports. In those documents, sensibly all views of the future theater environment show a highly distributed but highly connected information environment, with the backbone data-linking infrastructure generally labeled as the 'infosphere' or 'Cybersphere'. In essence the backbone for information reconnaissance in future theater environment will be a set of complex distributed data fusion systems consisting of (but not limited to) onboard and off-board fusion systems
Development of methodologies for electromagnetic susceptibility evaluation by John P Quine( file )
1 edition published in 1996 in English and held by 0 libraries worldwide
The contractor investigated the use of frequency modulated (FM), band limited noise signals and other applicable techniques to increase the speed of making coupling and shielding effectiveness measurements in reverberation chambers; developed the most promising techniques and analytical approaches for usable methodologies to predict the effect of electromagnetic fields on the operational performance of electronic systems; and developed and investigated new assessment techniques using reverberation chambers that will quickly determine the total amount of energy absorbed and/or reflected by electronic equipment as a function of frequency
moreShow More Titles
fewerShow Fewer Titles
English (24)
Close Window

Please sign in to WorldCat 

Don't have an account? You can easily create a free account.